Some good answers already here, but I can only answer for myself: I used to be that kind of leftist that was "Well I want socialism, but not like those scary foreign authoritarian countries. They're doing it wrong! Or that's not really socialism!" At some point after learning more history and talking with others online, I've softened my view on these places. Some of that is learning that some of what I knew about them was straight up misinformation, but some of it comes from a shift in perspective: These aren't abstract ideals of countries. They're real countries. With real people, real histories, real material conditions, real geopolitical relationships to deal with, etc. They're doing something really difficult and it's really easy to be an armchair quarterback while sitting cozy in the US where I don't have to deal with any of their tough decisions or the consequences of them. Am I happy with them doing some authoritarian policies? No. But maybe they're necessary to deal with the interference of the US? I don't know for sure if that's the best approach, but I don't have to imagine the counterexample of what it looks like if you don't take defensive measures, the US has helpfully provided a bunch in the form of all of the countries they've backed coups in for the crime of electing even a slightly leftist government. We could squabble about better ways to deal with this, but neither of us has the full context to have an educated discussion on the matter. Also for the genuinely bad stuff, I wouldn't go as far as specifically supporting those things, but it's worth putting them in perspective. You can't talk about China online without someone bringing up Tienanmen Square, meanwhile the US has been a never-ending avalanche of evil in it's short history, but you can talk about any number of things not related to politics in the US without a random leftist wandering into the discussion about the latest hollywood movie shouting the entire lyrics to "We Didn't Start the Fire." I mean we're happy to bring all that stuff up if it's in the right context, but people are so deranged about communist countries that the ONLY thing they can think to bring up in relation to them is their less savory moments that may or may not even be true/exaggerated.

It's really hard to sort good information from bad about these places because there's so much propaganda. I get that those other countries have an incentive to put out their own propaganda, but it's hard for me to know what their reach is or what their motivations are or how much they are lying vs countering US misinfo. Meanwhile I KNOW the US has a fairly sophisticated system of propaganda spanning government agencies, media companies, NGOs, etc. I KNOW the US is motivated to prop up the interests of capitalists and try to stop other countries from pushing back against them. A lot of the bad shit and lies the US has done is just straight up declassified history. So I'm sorry if I'm a little skeptical about what the empire that's made it it's business to deny self-determination to countries around the world has to say about those countries.

As for Russia, I'm not specifically a supporter. Ever since the USSR collapsed they've been another capitalist, imperialist country. But in terms of scale they're just not even remotely comparable to the US. They are at worst a regional power and outside of nukes can't really threaten the US on the global stage. So when the US war machine starts saber rattling about them, I know what it's for because I've seen it a million times before. We always need an external enemy to justify the massive amount of money we spend on the military and all of the capitalists who profit from it. Even if I think it would be good if someone in the region pushed back against Russian aggression, I think feeding the beast that is the US military industrial complex is a net negative for the world. Not that I really have any say in it. I can't remember the last time my congressperson or senator asked if I wanted to give another couple billion dollars to their friends in the "defense" industry. And then of course there was all the hysteria about Russian interference in our elections from the Democrats. I don't even care if they're right or wrong. That's besides the point. The function of the claims is what is more valuable to look at: The implication of "Russia is subverting our democracy by interfering in our elections." is "We had a previously uncorrupted democracy before the Russians got involved. Please ignore how our own billionaires have bought out all of our elections." It's a way to shore up support for a failing system by externalizing it's problems.

I just want to live in a world where we can all live dignified lives. US capitalists are the current greatest obstacle to that dream. I'd rather have imperfect allies against that than throw my lot in with the "Endless war, exploitation, and ecological collapse" team.