I think one of the most important things to keep in mind is that there are Soviet nostalgics and there are socialists (anarchists and communists).
Most people who are socialist out of politics and not out of a desire to see the old country relive its glory days are going to be very progressive on matters of race, gender and sexuality, animal rights etc.
Not all of them by any stretch of the imagination and, as an example, I'm in discussion with an anarchist outside of this platform who is saying really ableist and borderline eugenicist things so there's absolutely a whole lot more work to be done and I'll be the first to admit it. But generally I expect to see a fairly high standard of being progressive on these sorts of matters and I expect to see big, ugly intraleft slapfights that occur when someone is really backwards on these things (especially if it's an organisation.)
For example, you could ask most socialists what word springs to mind when they hear the phrase Communist Party of Great Britain/CPGB and they'll probably wrinkle their nose and say "TERF" lol.
For someone who is a communist, I'd expect that Soviet nostalgics and I would be 50/50 on finding common ground and on being in such disagreement that we'd butt heads and get into heated arguments over it. But it's also worth mentioning that I feel that would be the case for most people around the grandparent age.
I mean, I live in a racist shithole and when I meet people (especially white people) I kinda just brace for the racism. I present as masculine so I'm also bracing for the misogyny, mostly coming from other men. This tends to intensify the further back you go by birth year. I know that certain politics definitely attracts types of people (you're going to find more homophobes in a conservative party and you're going to find more vegans in a professive party, obviously) but I think a lot of your experiences with Soviet nostalgics could probably be attributed to a generational thing as well as the fact that in some countries Soviet nostalgia is, in a sense, a "conservative" or pseudo-conservative position.