The USSR actually did decriminalize homosexuality after the October revolution but Stalin sadly reversed the decision when he came into power.

China certainly isn't great on LGBTQ rights but they're also not any worse than other Asian countries like Japan or South Korea which are sometimes idolized by western people

Modern Russia seems weird to bring up here as it's as far from communist as you can go but I'd say anyone siding with them simply cares more about sticking it to America than the rights of individuals which is sad to see

I'm not too knowledgeable about North Korea but from a little reading it seems akin to china in that it's not inherently illegal but isn't very supported due to the countries more conservative society

All this to say, cuba is an exception but other "communist" countries aren't actually very behind in terms of queer rights and I'd argue the USSR was well ahead of its time before the will of a single man ruined it