If you click once on the planet in the diplomacy window and then click report it will tell you what their current ideology is.

Pretty sure that screen is just messed up thoroughly. I pick -2 relations for all my races, and I start with a ++ diplomatic skill bonus towards everyone. 

The Drengin may not care what Ideology you are. I'm still learning how diplo works but I know I believe they value each offense differently. Altaria HATES you if you are not the same ideology as them and the Kyrnn are worse. The Kyrnn are usually the first to declare war on me. 

First game played the game out of Beta I got my ass kicked by the Krynn (on Beginner, which was embarrassing). In the GC2 days I never really made a military in the beginnin. I focused on building up the infrastructure and diplomacy. Unfortunately that didn't work here. I started near the Krynn, they declared war and swarmed my colonies. And I had no defense and was having a rough time transfering to researching for military tech. 

I learned my lesson from that game: always have a small military at least, because who knows who is around the corner. The DRENGIN were nice to me but the Krynn? Eck. At least they act like zealots, now, though. 

This is one of my biggest problems with ideology right now.  Each ideology isn't so much an ideology as a choice of allies and bonuses, which kills immersion.  Evil races are pragmatic by design because they don't hate everyone whereas good races are hated by pragmatic ones...?

Choosing malevolent events should generally give you better bonuses but cause problems either for your civilization (reduced influence, population growth, population cap, approval, etc) or relations (excessively-high malevolence would even cause malevolent races to hate you because you are clearly a threat to them; you aren't malevolent only to good people after all...).  By contrast, benevolent events should be the worst bonuses but improve diplomatic relations or give civ bonuses (improved influence, population growth, research, approval).  Pragmatic would be the nice middle ground, fewer long-term bonuses but without the penalties either.  Having good races hate pragmatic ones too isn't necessarily bad, but only if it's the exception to the rule (and particularly, only hate benevolent races if they are acting on said hatred and killing everyone).

I also disagree with 10. My experience that benevolence has as many benefits as anyone else. Civilization 2 was imbalanced in this area

Explain to me why a malevolent faction should like a benevolent faction, or for that matter why a pragmatic faction should like a benevolent faction? If the benevolent are to be loved by all, does that include the malevolent as well? Is a benevolent faction allowed to hate anyone? If they are allowed to hate a malevolent faction and declare war on them, can the malevolent faction now hate the benevolent? But wait, the benevolent should be liked by all which implies that they should also like all, as well.

It is not a simple thing. It is very complicated.

A real world comparison is the, so called, benevolent liberals vs the so called pragmatic, or malevolent, conservatives. Do they like each other? Not likely. How about the Nazi? They are a perfect example of malevolent. Would you expect them to get along with a benevolent faction?

No one thinks of themselves as malevolent. Hitler probably thought he was benevolent, or at least pragmatic. With or without labels, people dislike each other because of the way their minds work. In Hitler's twisted mind, the Jews were malevolent and his decisions to oppress them were pragmatic. He was portrayed by his followers as a benevolent leader.

Several of the Roman Emperors are described by historians as good and benevolent dictators because of the social benefits that they granted to Roman citizens, but the decisions that they made in war were hardly benevolent to their enemies.

If you are only referring to how it should work in the game with no deference to reality, ideology and diplomacy works the way it works. The intent is for it to work as it does in real life. There is no intent that I am aware of to change the game so all factions love the benevolent and hate the malevolent and, I guess, feel completely neutral about the pragmatic. 

"Why should a pragmatic faction like a benevolent faction?"  Because a pragmatic nation has its own interest at heart, while a benevolent nation is willing to go out of its way to help other nations.  Most nations on earth are fundamentally pragmatic, and appreciate it when another nation is consistently willing to help others.  That alone isn't the main factor in politics, but people trust nations that help others more than nations that help themselves.

Should malevolent nations like benevolent ones?  It depends on whether they're somewhat cruel or pure evil (this game seems to have no in-betweens).  The answer is generally going to be no, but the problem is that in-game nations have just as much of a problem with benevolent cultures as malevolent.  The Nazis only made friends of people that either were also aggressive and common foes of Germany's enemies, or of nations that didn't want Germany to annex them.  By contrast, the Allied powers not only made friends of nations across the world that thought similar to them, but a lot of nations that very much didn't (USSR, Turkey, Brazil, China, etc).

That no one thinks of themselves as malevolent doesn't matter in politics.  The Soviet Union launched fewer wars during their reign than the US but it's hard to argue that they were better than the US because of this, particularly given the standard of living in Soviet territories and the Warsaw Pact versus NATO nations.  The longer people interact with a nation the more likely they will learn the truth (such as that Nazi Germany wasn't the beacon of industrious progress that many thought of it in the 30's), and in realistic terms it's not that hard for a nation's leaders to learn these facts.  The US population in WWII may have been isolationist but that didn't stop the government from actively taking steps during the early years to curb German and Japanese aggression (to the point of actively sinking U-Boats in the west Atlantic).  Portrayal as a benevolent leader only works internally (and even then not that well; a nation that looks stable because of propaganda usually isn't as stable as a nation portrayed as unstable from a free press), and it really doesn't work politically (where everyone else is used to those sort of games).

Roman Emperors being described as good and benevolent was because the people describing them were Romans and not Greeks or Celts; even a malevolent nation is likely to treat its own preferred class well, the only time a nation treats its preferred subjects badly is when its leader is a moron or they are in a time of serious crisis.  Rome varied from pragmatic to malevolent and that's why everyone who WASN'T Roman utterly despised them (during Spartacus's rebellion, Rome had just emerged from a civil war and was already facing a major revolt in Spain, Spartacus's slave rebellion, and a major confederacy of eastern states led by Pontus for the second time in a decade).  Whether or not someone writes about or speaks about someone in a positive manner doesn't mean that even during their own time that they were well-regarded.

Looking at the political parties of western nations is also a very bad way of pulling out "benevolent" versus "pragmatic".  95% of the time the decisions they make are pragmatic but the effectiveness of them are disputed, even when they are labeled as being "benevolent."  The arguments in favor of safety net programs are frequently that you're redistributing wealth to the lower class and enabling them to rise out of poverty, and the biggest debates politically are almost always a method of distracting people.  No one ever went to war over minimum wage, gay marriage, legalizing illegal immigrants, or universal health care, and national leaders don't exactly hold those to a very high standard.

The 3 ideologies are not good, neutral, evil, they are all different in the eye of the beholder.  Pragmatic is just as different to a Malevolent as Benevolent would be.  Hell, because Pragmatic has a bit of military capacity focus (mining, construction, trade) focus, does this mean they are more or less of a threat than benevolent?   But Benevolent has research and influence focus, which are 2 direct ways to win the game....so, they are ALL a threat to Malevolent.  

In fact, if a faction equally split all points between all 3 ideologies, which would it be considered?  IMO, it would be different than all ideologies and should receive a diplomatic malus against any extremist(a faction that puts all points into same ideology), but not as much malus as between 2 extremist factions with differing ideologies.

Just going to throw my hat into the ring:

First off, if you mouse over (or click, I can't remember) on the race in question, you should get a pop up telling you what your standing is with a particular race, and more importantly why you have this standing.  Conflicting ideologies are one of the root causes of war.

If you are a peaceful culture, it would make sense for a warrior culture to find this disgusting as it's a sign of weakness (remember the Klingons in Star Trek?).  The Klingons could care less how nice you are, but if you punch them in the face and tell them to sit down or you'll cut down their first born child with a Klingon ceremonial blade, then you will be respected enough to be "part of the club".

That's how it's supposed to work!  If it doesn't work that way, then there may be other factors preventing the faction from declaring war...

I think this (among other cross-ideology relationship issues) are already covered by the benefits that the tree gives you; it just comes at it from the other way around. Pragmatic gives things like increased Diplomacy (which partly offsets that particular penalty), war-proofing, penalties to another empire's morale when at war with the pragmatic civ, etc.

As for the other empires' ideologies, it does vary even though each race has a default preference, and there's a specific setup option to randomize their personalities (which presumably includes preferred ideologies) as well. Whether or not they get particularly irate about ideological differences comes down to their other personality traits: races that are "Spiritual" have much stronger feelings about their ideological preferences. Altairans are Spiritual/Xenophobic and the Krynn are Spiritual/Aggressive; put those together and you can see why they tend to blow their tops at anyone who doesn't share their worldview. (None of the other default races have Spiritual.)

Care to be more precise?