I will agree that the UI doesn't have the best learning curve, but it makes sense. There is a setting btw to put a background on the empire tree.
Beyond that, you have to understand the basics of the game's mechanics.
As for getting your fleet wiped by a capitalship like that... With any sort of user intervention, that could have been prevented. Long Range Missile Frigates typically can beat the crap out of capitals, but if you didn't build more given that you were under attack from two sources, that's your own fault. They are also the longest ranged units in the game.
And no, you don't have to be competitive on ICO against other humans to be good against AI. I'm fine against unfair AI's, but would probably get my butt kicked by someone who plays online. There are many ways to fail and many ways to win. Also, if you were trying to fight even normal AI's in your first round of plays, that was bad on your part. Watch some replays if you actually want to ever try the game again.
Oh, and just so you know, being disgruntled with a game does not give you permission to come online to the forums, rave, and spew profanity. It does give you permission to calmly ask what you were doing wrong and how you can improve.
As for things you were probably doing wrong... Capital ships are powerful, but do not typically constitute the bulk of a fleet. They shouldn't. They are there for their abilities and not damage beyond the very early game. Some abilities like the Marza Dreadnought's Missile Barrage are absolutely game changing once you acquire them. Missile barrage for instance pounds every enemy ship within range with enough damage to kill most ships in the game. Of course, the thing takes more than 30 seconds, which is plenty of time for a player to move his fleet away from it because the Marza can't move while using it.
Also, gauss defense platforms and orbital hangars are nice and can defend against a small fleet, but in the end, there is no replacement for a real fleet. That said, in Entrenchment, an expansion of Sins, there are starbases which are far more powerful, but you are probably not even interested in this game, so why am I bothering with Entrenchment? Anyways, ships themselves are far better than static defenses. Static defenses should supplement your fleet when defending, not replace it. The TEC especially have to obey this. They have the best repair platform in the game by far. It heals a huge amount of health over time and if you have three within range of each other, they can keep a fleet near them alive with ease.
Also, certain ships have combat bonuses towards other types. For instance, Javelis Long Range Missile Frigates are extra-good against Cobalt Light Frigates. For a better explanation of this, head to the strategy section of the forum and start looking. I made a graphical one a year or so ago, but it is still accurate. It should make more sense than the charts you'll find there as well.
Also, don't rush into research. Research is expensive and often times, you could be doing better things like building your fleet. Ideally, you should be expanding at about twice the rate of the AI. Now, that may seem difficult now, but I assure you, it can be done.
Another critical point here is that you should always consider what the advantages to your fleet as a whole there are. Kols are nigh unkillable, but do absolutely nothing aside from slaughter strikecraft (fighters and bombers). Sova Carriers on the other hand are a great way to start a game that is close because of the varriance of its abilities. It produces strikecraft, can pump out stationary missile turrets, can steal the income of an enemy planet (very very handy on Point Blank) and can increase the power of its strikecraft.
Also, Don't try to rush to colonize volcanic or ice worlds. Those asteroids are nice, but if there is an asteroid nearby, grab it instead unless you have a sufficiently sized fleet and are ready to research. Asteroids are easy to capture. Two Cobalts is enough to wipe out the Cobalt and Krosov found above neutral asteroids.
Oh, and don't try to upgrade your planet in every manner possible. Upgrade as needed, not just for the heck of it. The starting order is almost imperative however:
- Build 2-3 scouts (and send them on their merry ways exploring as soon as they are built)
- Capital Factory
- Asteroid Mines
- Population Upgrade/Weapon Research Lab (your choice).
- Build Capital
- Scuttle Capital Factory
- Begin Expansion
I don't recall if vanilla Sins has quickstart or if that is only in Entrenchment and Diplomacy (another expansion), but quickstart does 1,2, and 3 for you. They have to come first. If they don't, you're already behind.
Let's go back to Point Blank again against an easy AI. Do 1 through 4 and then build a Sova Carrier and a few cobalts and a colony frigate. Build 1 fighter and two bombers and set the first ability to Embargo. Launch two cobalts against your nearby asteroid and take the rest with your sova to attack the enemy planet (which is next door). Embargo will give you a huge advantage because at this point, they are only getting income from one planet (as are you) and you are stealing their already low income. This will handicap them and enable you to build more. Send the fighters after the construction frigates and the bombers after the factories. They will probably have built a capital by now as well as a few light frigates (for the TEC, these are Cobalts). Continue to fight, but don't forget about that asteroid which should probably be clear of enemy ships right about now. Send in your colony frigate to colonize and buy the first population upgrade (otherwise you'll actually receive negative tax revenue which could have been a mistake you were making) and the asteroid mines. Then build another Cobalt or two and send them to the asteroid to link up with the one that survived the battle from earlier. Send these through the star's gravity well and start harassing the enemy's asteroid (if they haven't colonized it yet, they will soon). Do as much damage to structures as you can, especially construction frigates. Without them, the enemy can't build anything to defend themselves against your ships. Also, every structure you destroy is resources down the drain for them. If you can keep up the attack on both fronts (their homeworld should be the main front since it is the one giving them the most income while the asteroid is just to keep them from getting the upper hand.
Eventually, you should wipe out their fleet and asteroid, leaving their factories wide open. Destroy them, and they are doomed. With neither construction frigates nor factories, you cannot win. Press the attack and bomb their planet with their sova and send the rest of your fleet to attack the constructors when they respawn.
Hopefully that'll help, but I think in your case, you just chose to rant for a few minutes and make a bunch of people mad whereas I took quite a while to write all this... More than you deserve, but hopefully you'll understand my point and be more mature. If not in Sins, at least in life as a whole.