The US being wrong does not make its enemies right. I don't think that right now, in the current way the world is, there is much of a "good side" because most countries are doing horrible shit. If you start going for the lesser evil, you accept that as the new norm and it continues worsening.
Yes, I do disagree. Because even if it were to be true, Russia is still doing things in the worst possible way. Ukraine is having nazis? Then influence their elections (which Russia loves to do) to make them shift away from it. Find economic or political leverage to pressure them. Setup rescue operations or diplomatic passage for the potential victims. But steamrolling the whole country, killing basically everyone you can on your way? I'm sorry, that's not how it works.
If Ukraine is made of nazis, then the nazis must be taken care of, yes. But what Russia is then doing (assuming that what you've been saying were to be true), is the equivalent of the US dropping a bunch of nuclear bombs on a Japan at the brink of surrender, or of the winners of WWI dismantling Germany to "punish" it for its leadership, or of Israel trying to conquer and destroy all the countries around it that it doesn't like. Or even, of all those western countries that use the excuse of counter-terrorism to consider every individual a potential threat that deserves death. It's an oppressor move, and these cannot be supported.
A powerful country like Russia has many ways to solve any conflict or problem, and if they pick the violent, oppressive, indiscriminate way, then they are wrong.