It's as if every single topic, person, game, etc is just racist/sexist/transphobic in waiting. Once someone has declared it to be so, then it just is now, and there is no arguing against the claim
Exactly. They'll go on about how minority groups aren't hive minds, that they're allowed to have differences of opinion - that's usually something they'll say when you, for example, quote a black person they don't agree with.
But if a single person in a minority group says something is bigoted towards them, then yes they
do represent all of them. Being offended is the one thing they can all agree on, apparently. Which is where the above situation comes in, because it doesn't matter how many black people you can point to who say something isn't racist - you only need the one, and then suddenly all the rest are just misinformed or internalising whiteness or whatever buzzword bullshit they want to throw at you.
The reality is that ResetEra, like numerous other forums, is in a constant purity spiral. And the people who win in that environment are the most thin-skinned, autistic cunts who think everything that doesn't validate them is a personal attack, and all personal attacks can only be based on what they are rather than who they are because they're narcissists. Nepenthe is a great example of this, in that one of the subtexts of her posting style is that the only reason people don't like her is because she's spitting truth-bombs that make them uncomfortable, mostly involving race, gender and gender identity. Being called things like 'arrogant' and 'abrasive' she takes as compliments, because in her mind that's other people's discomfort with her existence, not the fact that she's, well, an arrogant bully who treats other people like shit under the guise of social justice. I'm certain she's said in the past, 'but y'all aren't ready to have that conversation' - a phrase high in the running for most obnoxious phrasing to be used on Twitter, among some incredibly stiff competition.
In places like ResetEra, a minority taking offence gets to force the conversation to go the way they want, and only normal white people will ever be told they're overreacting. Part of the SJW conditioning is to never concede that this creates an incentive for people to be offended early and often, to hold onto grudges so chosen topics can only ever be people agreeing with them, and then of course to start lying about their minority statuses to be permitted to speak.