The Federation is arrogant, but it's not evil. Nor is it corrupt as a whole. They may be some corrupt members, though. Anything touched by humanity will have that dynamic.
The Maquis issue was essentially a serious mistake, unfair to them and beneficial to the Cardassians. I'd admit that the Federation screwed up with that one.
But there are dozens of episodes in TNG where the Enterprise is sent out on a Federation mission to achieve peace or rescue a civilization from disaster. Most of the time, the Federation succeeds in helping. Seems more like a "do good" organization than "do evil," doesn't it?
Yes, the Federation does want other space faring peaceful nations to join it. But they don't demand
it. They don't conquer you if you resist. A civilization has to apply to join. They can choose not to, and the Federation respects it. So... what's the problem?