

Short answer: Many people support those governments critically or uncritically for various reasons.
Long answer:
Russia: Some people who oppose US hegemony support Russia as probably the most effective anti-US actor globally - I mean look at what they’ve managed (in part) to do to the US government over the last 10 years or so. They may also be sympathetic to Russian anti-NATO sentiment. People who support China may also critically support Russia since they are a strategic ally of China. Some people just full-throatedly support Russia uncritically - I don’t know why they’re quite so enthusiastic, but most others who have pro-Russian sentiment are still critical of Russia, but support them as a major power capable of attacking US hegemony.
China: China is the most successful communist country to have ever existed. Many left-leaning people may support China to varying degrees because they are an Actually Existing Socialist country and because their model of Communism with Chinese Characteristics seems to work quite well for them. Due to the West (broadly) attacking Socialist governments in the name of Liberalism & becoming increasingly more fascistic, China could be an important bulwark against fascism. Many people support China uncritically - they genuinely like the Chinese system of government and want their governments to be more like China’s. Other people critically support China - they believe China’s government is problematic in some way(s), but support it anyway as a bastion of socialism and a significant challenger to US economic & political hegemony.
As for support for the governments as opposed to the people: We kind of have to talk about these things at the country level, since governments are the (imperfect) embodiments of political ideologies and collectively act on behalf of the people within their borders, and “the people” aren’t monolithic. We often treat countries as avatars of political ideologies which is inaccurate but is an abstraction that unfortunately often leads to an oversimplification of the ideologies behind & effects of those governments’ actions while allowing us to create a comprehensible narrative.
This is one thing I think about with AI and technological progress. Optimists say that technological advancement could free people up for more creative work, fund UBI, etc.
I think that without a serious overhaul of the legal and societal frameworks of Western countries, jobs that only people can do well or are too costly to automate could become the only way to earn a living for most people.
Like sex work, for instance. The poor underclass would expand, the wealth gap would widen and labor exploitation would become much worse. Voíla, suddenly children seeing prostitution as an aspirational career becomes more common because that may be an increasingly likely eventuality.