As for the "kicking their ass in self-defense"-how does that apply to the movie? The Baku didn't win the fight, they had someone else do their fighting for them. If your point is "have the Baku fight it out with the Son'a," then I'm fine with that, but the Son'a still win. It doesn't exactly endear the Baku to the audience that they are "pacifists" who are happy to let others risk their lives and fight on their behalf. And the ending pretty much guarantees that the UFP will be committed to defending the Baku from now on. I'm sure Starfleet officers are thrilled about that prospect.
Just as thrilled as any soldier who has to protect people who can't or won't defend themselves, I guess.
not quite. Usually soldiers defend members of their own political unit, be it a tribe, state, or nation. But that doesn't apply here, because your argument is that the Baku are neutral, and most definitely NOT part of the UFP.
Also, the soldier in this situation is aware that he is defending a group that are hoarding a resource that could cure all of the various folks back home who have various diseases or ailments, but that they have no interest in helping anyone but themselves.
So a bit more bitterness there, probably.