If one wants to pick and choose "right" conflicts, one shouldn't serve.
And ultimately... while I know HN has a pretty anti-authority bend... if you don't trust your government to deploy military power, what do you trust them for?
Which isn't saying that uses of military power in reality are always right or justified, but is saying that effectively every other government power rests on top of its having the authority to use force to enforce compliance. And a military is a major component of that.