USSR was brutal. World War 2 was extremely brutal - they lost 30 million people
Anyway it is all war crimes, I totally agree !
I don’t know if it is “just” because Russian officers wanted their land. They already could get land through crooked courts easily.
USSR was pissed at how rabidly some Ukrainians and others killed people when they sided with the Nazis. I am Jewish and two sisters of my grandma were brutally killed by Ukrainians (not Germans) while being under 10 years old. One German wanted to quietly save them but the Ukrainians wouldn’t let him.
People want independence and appeal to have their rights, but during war time they can often abuse weaker people too a lot.
As far as Tatars read the last two paragraphs here: https://www.jewishvirtuallibrary.org/krimchaks