The game is a sandbox and one's RP can impact another's.
Claiming to have influence over a governmental entities make-up (the Senate) and therefore the course of the Federation impacts the play of players claiming loyalty to the Federation. At some point, these characters might claim that their party is supporting legislation to strip Soter of his rank and that he no longer supports the Federation.
If Soter (or any player) previously recognized the legitimacy of these characters, he has now given up control of his roleplay to another player.
Just letting others have their fun has implications on an individual's roleplay.
I think there is a key point here, though. You have to choose the let people into 'your' part of the sandbox, and you even choose the terms on which they are allowed in. I probably wouldn't interact with these people IC. My feeling is that they are over-reaching with some of their claims, etc. I mean that only in relation to what I would feel comfortable involving my characters in.
That doesn't mean that they are doing it wrong, and they have no control over my RP except what I
choose to give them. Interaction lends legitimacy.
I think they should feel free to RP in whatever way they want. There is no requirement that anyone else RP with them if they don't like it, and if you do choose to engage them IC, you can of course do so by calling them crazy or whatever else you would like.
I think if you feel it necessary to bring in game mechanics etc, you might stop for a moment and evaluate exactly how much of a negative impact they are really having on your gameplay, and if it is really necessary to jump through those kind of hoops to try and discredit them. There were times, earlier in my RP career, when I started down that path, because it is satisfying on some level to go, 'Ah-ha! That's against the rules!' I'm careful not to do that, anymore, because I realized that it added virtually nothing to my game, potentially took something from other people's games, and that ultimately any 'game mechanics are like this so you have to do things this way' arguments I made could well one day be turned on me, when I wanted to do something interesting and slightly outside the box.
My own experience in this area was the Happy Chip thing. Someone pointed out they were not an item that was on the market IG, and it wasn't a big deal - 'they're somewhere in consumer electronics, etc'. I'm sure they or someone else could have made a bigger deal out of the fact that the entire thing was, you know, make believe OOC. Noone did, and I think a lot of fun was had by all.
I'm sure there were people who ignored it, because it wasn't their kind of thing, and that's fine. Similarly, I think when people create opportunities for others to derive enjoyment from the game it's wonderful, even if they aren't all the sorts that appeal to me or that I feel would fit in comfortably with my RP.