How would you respond if someone said something like:
"The literal-minded personalities we often encounter in the engineering profession are just not cognitively capable of handling leadership positions. They suffer from autism, a form of mental illness, and while they are fit for highly logical and problem solving tasks are not fit for tasks that involve social or political decision making. It's important that they be kept away from positions of influence or outward-facing communication and properly managed."
Would you call for that person's resignation? I sure as hell would.
If Stallman thought UFOs were clearly alien spacecraft or that Bigfoot was a real surviving prehistoric hominid, I don't think anyone would care. If he took some positions that were more politically charged, like denying evolution or climate change, people might get mad or call him names but I doubt they'd call for his resignation from the FSF or MIT over it.
There is no broad based "witch hunt" against divergent opinions, but there is a new-found extreme intolerance for a certain narrower set.
The opinions in question are those that denigrate other human beings or deny them equal rights or dignity, such as the choice to engage in pedantic hair splitting to defend the sexual exploitation of children.
Other well known cases of "cancel culture" follow the same pattern: Brendan Eich apparently funding campaigns to deny rights to homosexuals, a Google engineer taking the time to write a wall of text explaining why women are "on average" less suited for engineering work, and so on.
So the question becomes: do you think it's right for society or our peers to react so strongly to those kinds of opinions? Is there value in debating them?
P.S. As for the extreme reaction: sexual abuse of children and adolescents is fairly prevalent. Statistically it's pretty likely that at least a small double-digit percentage of free software authors and people involved in the free software community are victims. Seeing Stallman go out on a limb to defend or at least apologize for that kind of thing probably angered quite a few people for reasons that are entirely understandable, especially in the context of his past comments about pedophilia. Sometimes it's tough to see what the big deal is when it's not about an issue that directly relates to you, hence the artificial example I wrote up above.