chapotraphouse

Those were part of the broader proxy wars to crush the USSR

Cool. I guess destroying your allies on behalf of the worst empire of the world is a great strategy. I suppose, you would support another socialist project nuking the PRC to 'play both sides'.

A lot of this really just comes down to how politics work in the real world. None of that idealistic fantasy about siding with the people we like or don’t like.

Okay, so, do you suggest that the USSR should have abandoned helping anti-colonial liberation movements around the world and put effort into just allying with the US, liberalising its economy, and destroying the PRC, preferably before it even formed?

You are yet to actually explain how destroying your allies is helpful.
It is also rather clear that you aren't exactly interested in international solidarity or in socialism prevailing in the world in general.

The photo that OP posted happened just a year after the Prague Spring when the USSR invaded Czechoslovakia, and months after the USSR and China clashed in a border skirmish in 1969. From China’s perspective, the Soviets are showing their imperialist ambitions and they have to be stopped at all cost.

So, the PRC helping the most prolific imperialist force in the world that is carrying out genocides even today, and which has been engaging in colonialism in general by destroying its own allies is completely fine realpolitik that everybody should engage in, but the USSR attempting to prevent liberalisation and potential alignment of a state with NATO is bad? I guess the USSR should have instead armed a pro-NATO militant org there instead.

Apparently, the imperialism of NATO shouldn't have been stopped at all costs, if you are to be believed.

EDIT: It honestly feels like you are trying to just invent a way to present the PRC's foreign policy at that time as some sort of masterful 10D chess strategy, when it was clearly a major misplay, whether you consider realpolitik or not.