In my experience there really is no correlation between being powerless/oppressed and actually being a good person: plenty of such people when given a bit of power turn out to be the same kind of shithole as the ones who oppress them in other situations.

The reason why powerless/oppressed people seldom act as shitholes is not because they're better persons in average than the rest, it's because they're far more likely to suffer negative consequences if they do act in such ways, than the powerfull are.

I think the OP's experience is the result of this dynamic alongside the one that, when that in an online environment one is far more likely to notice the assholes (because they're the ones activelly posting shit) than the non-assholes (because they're more likely to just silently negativelly judge the assholes) - in a street you can see when there's a ton of other people looking down on the assholes, but you can't online.

In my experience the solution for this kind of problem in an expert context is to keep in mind that the most expert a person is, the least likely they are to waste time in shit-talking, so almost invariably the people being assholes online in such a context don't actually have knowledge beyond at most mid-level expertise and are really not deserving of any respect on a professional sense and, of course, as people who would chose shit-talking rather than helping or at worst not bothering and staying silent when confronted with somebody with less knowledge, are not deserving of any respect as persons.

Further and given the whole "generally powerless person who will act as an asshole if they're isolated from the consequences of it" dynamic, they're only doing it because they feel isolated from the consequences of pissing of somebody else, but that means the other side is also isolated from them.

Dealing with such people in a work environment is a lot more complex, but online they're like dogs barking behind a wall and just as unworthy of consideration or attention.