I agree with you with regards to the Feds.
You are probably right with the Imps too, however Imperial law would contest 'disposable' in strong terms. However we know from Reclamation that what Imperial law says, and what happens might not be the same thing.
The Alliance is the interesting one. Define 'traitors'. To my knowledge that comes from a tongue in cheek remark from Michael Brooks which he then said should not be taken seriously. Of course others have suggested he may have then been backtracking, but I tend to take him at his word.
Would trying to sort out the mess left by the Feds and Imps joint INRA actions, and thus saving Humanity from being royally wtfpwnd by the Thargoids in a very final way, be classed as treason? Or saving the Feds and Imps sorry asses despite themselves?
If aliens had arrived at Earth during WW2 and the Allies accepted their help to defeat the 'very bad political party in Germany in the 30s and 40s whose name it would seem is blocked', would that make them traitors to humanity?
EDIT: I think the danger here is adopting a very old fashioned, us and them attitude, based on appearance (race, colour, nation or in this case species), as opposed to taking a (quite literally in this case) Cosmopolitan (the true meaning: citizen of the cosmos), view and seeing sides based on there actions and principles not the shape of their mouth parts.
The view of The Alliance as traitors goes back to before M. Brookes. I'm referencing the end of Frontier: First Encounters which, now, appears to not be canonical. When "Dangerous" was released though most of us thought that the old timeline was still "intact" and that's one of the reasons why I through my hat in with the Federation instead of the Alliance. Given the fact that the revised timeline no longer reflects the way FFE ended I might have chosen my allies differently ... but now I'm too deeply entrenched thanks to way too many in-game friendships.