So all art featuring architecture that doesn't have it actively being built or features someone holding a hammer in the foreground is fascist?

Is this fascist?

All I'm getting out of this discourse is Solarpunk art needs more twinks or bears (pick yer poison) in dirty overalls installing solar panels and geodesic domes

What, so you're saying:

Westerners need to fantasize less about the complete reorganization of society into something utterly unrecognizable and focus more on how to take control over the ugliness that already exists so that they can chart a better course for their countries, as China has.

That being said, it's a huge stretch to compare it to social fascism. While it is political in nature, I feel its merits lie more as a literary and artistic counterbalance to dystopian worldbuilding in the west

Honestly, taking it as its worst, an aesthetic artistic movement is based on aesthetic, and frankly I don't see a lot of harm in that, at all, but it's not good if one is stuck on it, as an end-all

I think its role is similar to that of religion, albeit more benign

Religious suffering is, at one and the same time, the expression of real suffering and a protest against real suffering. Religion is the sigh of the oppressed creature, the heart of a heartless world, and the soul of soulless conditions. It is the opium of the people.

The abolition of religion as the illusory happiness of the people is the demand for their real happiness. To call on them to give up their illusions about their condition is to call on them to give up a condition that requires illusions. The criticism of religion is, therefore, in embryo, the criticism of that vale of tears of which religion is the halo.

Socialist realism celebrates the worker as creator with muscles straining, tools in hand, actively building the world

Do you actually have a conception of Soviet & socialist art outside of the Western propagandistic portrayal of it? Now, I'm not an art historian or anything myself, but I'm pretty sure it was not in fact a Japanese bara manga about big sweaty workers with their hulking muscles swinging hammers around. The Soviet Union was a big country, with many separate republics and ethnicities (hence the name!), and I'm sure a variety of styles and artistic movements.

The Soviets were also pretty big on resorts with spa-style facilities, so portraying workers as only ever working wouldn't have even necessarily been the ideological line, especially after the Stakhanovites went out of fashion. And a bunch of socialist realist paintings aren't of workers at all, they're just Stalin or other important figures standing around looking cool