I rarely see criticism of actual misdeeds, mostly vague “USSR bad” and shit either made up or taken wildly out of context, both of which serve no purpose but to attack all of socialism’s principles.

Do you view criticisms of the USA as criticisms of democracy's principles?

If not, then you're being irrational in how you think about one or both of the countries.

This is the equivalent of starting every conversation involving Israel with “Do you condemn Hamas??!”; even if Hamas is imperfect, condemning them in the context of resisting Israel is condemning actual existing resistance to genocide.

Most reasonable socialists agree that the USSR perverted a socialist movement to benefit a new ruling class and oppress people. As such, the USSR was a significant blow to socialism in more ways than one. I think it's perfectly reasonable to criticize something that was more Bad than Good, even if it had some Good.

Again wrapping around to the USA, I would wager you have no qualms with criticizing the USA even if it does some good.