This is some doodoo. So if your opponent is going to rickroll you, you have to whack out some quick research to offer the pirates a mission? IMHO, it should be money based.
He's saying that if you have little fleet supply, but your enemy has a lot, you can send large raids.
If you have lots of fleet supply, but your opponent has little, you can send small raids.
This is likely to stop powerful players from absolutely steamrolling the game. If you have 100K credits to drop, odds are you have a pretty good economy, likely a pretty good fleet, and high level researches. You are at an advantage.
Meanwhilst, your opponent may have 20K spare credits that they saved up because they can't overrun your economy, your forces are too powerful to defeat, and they're never going to catch up to your research level. As such, they can save their resources and send the pirates at you. It tried to give them a fighting chance, rather than giving you the ability to steamroll them.