A good deed done for the wrong reasons is still a good deed. The reason why NATO is the lesser of two evils in this sense is that between two brutal authoritarian regimes, NATO is significantly more hands-off and more open to being manipulated by civilian interest than the more brutally right-wing Russian regime. One of these exploitative imperialists will probably let you get gay married, the other one will kill you for it. The US military industrial complex will pick a target regardless. It may as well be a target that ends up counteracting Russian imperialism; I'd rather have those bullets in Russian corpses than, say, whatever country Saudi Arabia has decided needs bullying this week.
Anyways, the core of the issue is that it takes a LOT of hand-wringing and "b-but both sides" to justify active warfare to sit back and let an imperial power shit hellfire down civilians' throats. Anyone who actively supports pulling out of Ukraine is, bluntly, just kind of an idiot.