I'm not a fan of Mearsheimer here (he was wrong on whether Russia would go to war for one thing; for another, he extrapolates way too far in ascribing motives to Putin/Russia that he doesn't have evidence for) and I think states are generally security maximizing and not power maximizing.

But Mearsheimer's book title of "The Tragedy of Great Power politics" is apt. Because the tragedy is that states have different interests than the well being of the people that live in them. I don't think pointing that out is immoral, quite the opposite; hard truths are still truths.

It's more accurate to say that some ukranian people have ousted the president and let US decide whom to put in place

The country was split nearly 50/50 between pro-us and pro-russian. Surely enough the second half was cancelled after the coup (change in language laws for instance).