It's become strawman arguments to create different tribes. The issue isn't about China or what they do well or do badly. The "facts" and accusations against "tankies" are just taken as given.
Prejudice has become mainstream and a serious problem because people are just fed up with actually arguing. I think it started with the global warming denial. we learned that it's not just fringe groups that are simply immune to arguing, but that you can have half of the people be immune to political discourse. And of course Russia propaganda played a major role in that, but much less than the climate denial or religious or libertarian propaganda that comes from think tanks and the Koch brothers and Murdock and other plutocrats.
As a radical and dissenter myself, I'm not pro Russia or pro China but I see them as a country of human beings and see how the propaganda against them is used to deflect both blame and attention away from the dominant world order, "US centric imperialism". The "leftists" and "progressives" point their finger to Iran or China or Russia about the LGBTQ or whatever issues over there using mainstream media or memes, instead of primarily focusing on the responsibility of their own actions, the actions of their own countries. The effects of soft power, the effects of "economic imperialism" on other countries, and their ignorance of what regime change actually means for the actual quality of life of those people living in "shithole" countries. Liberals don't realize how redpilled they are, how "unwoke". Hate sells really well in the attention economy.
Almost nobody on "those instances" believes Russia or China is socialist. It's simply that a unipolar instead of a multipolar world will mean much less hope for any socialist projects to succeed. Constantly painting them as "evil" and threatening them with military expansion is also just wrong.
Many have done that for decades, but the tend remains that the internet is getting less and less free.