I read a decent rebuttal to the “paradox” of tolerance. To summarize for those that don’t know, the idea is that tolerance is a social contract. You tolerate everyone that’s behaving according to the contract. Refusing to tolerate someone that has broken the contract isn’t a violation of the contract; it’s required in order to enforce the contract.
You break the rules, you lose the protections. Simple as.
Have you met these people IRL or online? Most of the people I’ve met online do fall into one of those two buckets, but almost nobody I’ve met IRL does.
I would assume this is selection bias before attributing it to some other thing. The kinds of circles you run in are going to heavily affect this.