(even when you return to a system controlled by your power they put you in prison for fighting back against an enemy power!)
Yes - there are major problems with the
rest of the crime system in both directions.
This happens plenty outside a Powerplay context too - faction A can send you on a mission to attack faction B; in the course of this you can end up getting a bounty with faction A for the mission they sent you on, or faction A caring about the notoriety you built up attacking their enemy. Powerplay is at least a bit better in that your own Power will never punish you for acting in their interests (but minor factions might still try)
Conversely with the minor factions (who are the implementation point for the crime system) there are quite a wide range of things which obviously hurt a faction's interests for which you won't be punished at all. For example, you can blow up a faction's warships in a CZ all day long and never drop below max-Allied with them, provided you always leave before the CZ completes, and still potentially lose them control of the system just from the combat bonds cashed in.
Scrapping the whole current legal system and replacing it with a more consistent "are you hurting our interests? then we'll hurt you" system (as Powerplay does, as Odyssey settlement gameplay does) would be a big general improvement, though rather a culture shock for the existing non-Powerplay spaceship part of the game.
i mean, why is Winters killing Aisling supporters, or Aisling killing Arissa supporters? Doesn't make sense.
While a 12-way peace treaty between the Powers would probably get majority player support for each individual pairing of it, Frontier
were trying to make a competitive system, however unsuccessfully, so having the Powers be able to undermine each other is a necessary part of that.
Justify that in lore however you like, or decide that there's no plausible lore justification (as with 99% of the gameplay, of course [1]), whichever. But a competitive feature needs some actual competition from time to time, and the ED setting is violent enough that "shooting the other side" makes sense as part of that.
[1] One of the sillier examples staying in the "legal systems" area: about half of government types ban trade in personal weapons. If you try to smuggle a canister of those into a station and get caught with it, that's a substantial fine. Those same governments are all
absolutely fine with you walking around their secure facilities carrying three of those weapons, provided you don't actually draw them. They'll even sell you some more, or buy your spares. This makes as much logical sense as anything in Powerplay - i.e. not much - but you never get players suggesting that democratic/corporate governments should close the Frontier Supplies services on concourses, or at least only sell suits rather than weapons there.
The others should very much be doing it subtly. Via missions, or organised disruption.
Yes. And when you get
caught doing this subtle stuff? That's the point that you get very unsubtly shot. Or, if you're in your own Power's space, that's the point you get to shoot the enemy agent trying to subtly undermine your system, of course.