Putin launched a war for what he perceives to be historical reasons. The work of 400 years of Russian Czars can’t be left behind. His contribution to Russian history as he sees it is to recover it. That doesn’t make his actions right! It just makes it understandable. Why is it so hard for people to understand that?
And to that he has killed more Russian speakers than any Kremlin leader since Stalin. Why is it so hard to understand how wrong that that and why it must be stopped?
Foreign policy by moral crusade is poor policy. Do you want to invade every despotism and set things right? We've been doing that lately in places where there was at least an arguable US interest and it hasn't worked out very well. One despot is replaced by another even if he's our despot! As LBJ once said in reference to a South Vietnamese leader - “He may be a SOB but he's our SOB!”. As we know that didn't work out so well either!
Russian history and culture (or Ukrainian for that matter!) still hasn't evolved to a level where some sort of rational government with rule-of-law and equality-before-the-law is possible. Unfortunately we seem to be devolving where we can't do it either.