[Ifroham4]

"It was considered a war crime at that time when Nazis killed prisoners."

Not (legally) when they shot partisans who were out of uniform. The 1929 Geneva Convention did not protect such fighters, who were not POWs. "Prisoners" is not specific. The sort of prisoner matters. The Allies shot Werewolf partisans in Germany after the war. It was equally legal.

"What else do you admire about the Soviets?"

They destroyed the rotten Tsarist government, unified their country, and forced it into the modern age.
They weren't nice about it and their methods were poor compared to those of China, but they are not a Germanic protectorate because their methods worked.

They also had talented aircraft designers. Should I reject their designs because they were built by the Soviet aviation industry?

FWIW, I don't respect law in cultural war, though I can debate it in that context. We only need law if it serves our culture, because law is not more than a convenience for maintaining social order. It is an important convenience, until the enemy shelters under it. Once that happens, we don't need it any more.
Whenever anyone argues that law should shelter cultural enemies, they are either such an enemy or are childishly delusional. If law is a weapon against the society it supposedly protects, then it is time to put other, different, sentences on paper and to do other, useful things as a matter of situationally appropriate custom.