Do you really think the existence of oppression is a figment of Marxist ideology?

I'm perfectly happy to accept the existence of oppression, but I see no need to make up ways in which the oppression might be even more awful than one had previously thought. Isn't it enough that peasants live shorter lives, are deprived of stuff, can be abused by the wealthy, etc? Why do we need to make up additional ways in which they might be opppressed? Gould comes off here as engaging in a horns effect: not only is oppression bad in the obvious concrete well-verified ways, it's the Worst Thing In The World and so it's also oppressing Einsteins!

If being poor didn't make it harder to become a famous mathematician given innate ability, I'm not sure "poverty" would be a coherent concept.

Not what Gould hyperbolically claimed. He didn't say that 'at the margin, there may be someone who was slightly better than your average mathematician but who failed to get tenure thanks to some lingering disadvantages from his childhood'. He claimed that there were outright historic geniuses laboring in the fields. I regard this as completely ludicrous due both to the effects of poverty & oppression on means & tails and due to the pretty effective meritocratic mechanisms in even a backwater like India.

Even if the mean mathematical ability in Indians were innately low (I'm quite skeptical there)

It absolutely is. Don't confuse the fact that there are quite a few brilliant Indians in absolute numbers with a statement about the mean - with a population of ~1.3 billion people, that's just proving the point.

to become a mathematician, you have to, at minimum, be aware that higher math exists, that you're unusually good at it by world standards, and being a mathematician at that level is a viable way to support your family.

The talent can manifest as early as arithmetic, which is taught to a great many poor people, I am given to understand.

I'm fairly confident that confessing to poisoning someone else's food usually gets you incarcerated, and occasionally gets you killed (think feudal society or mob-ridden areas), and is at least a career-limiting move if you don't start from a privileged position.

Really? Then I'm sure you could name three examples.

Goedel didn't become clinically paranoid until later, but he was always the sort of person who would thoughtlessly insult an important gatekeeper's government, which is part of what I was getting at

Sorry, I can only read what you wrote. If you meant he lacked tact, you shouldn't have brought up insanity.

Ramanujan was more politic than your average mathematician.

Really? Because his mathematician peers were completely exasperated at him. What, exactly, was he politic about?