Those are also lies, probably. Read all the comments here - or link to an actual instance of "additional info here and elsewhere" and I may be actually able to link you to a denial/ proof that it's fabricated. Eg. the most egregious stuff I've read against him was published by Gruber aka "daringfireball", and were all proven to be shameless lies (and rather obvious and easy to dispel ones, after one learns a bit of history about RMS. Like, that he was never married, wasn't on the board of VA Linux, etc)
These are very different levels of "wrong". Forced sex is much worse than consensual sex.
No basis is offered for why we should think this is "most plausible", except that Stallman likes Minsky and does not think it plausible that he did a bad thing.
There are some summaries which misrepresent what he said, but what he actually said was definitely something people could reasonably object to, especially given the longer context of him saying crazy stuff on related topics before.
I admit I haven't been following this news very well so far, so I'm doubtless missing some important facts. I'd heard Stallman was stepping down because of something he said about Minsky, but I have no idea what that was. If this is it, and this article is correct (edit: based on additional info here and elsewhere, it seems Stallman has a long history of questionable behaviour towards women that was also addressed in the initial article, so this new article is omitting quite a bit), then I'm baffled that he has to step down from anything. What he said, that the girl was coerced to appear willing, seems pretty clear to me, and presenting that as him saying that she was actually willing, sounds like a pretty clear and blatant lie to me. Seems worth criticising the organisations that spread that lie.
I'm generally in favour of fighting rape culture and child abuse with all that we've got, and Epstein is clearly pure evil. If Minsky has sex with an underage girl, it doesn't even matter whether she appeared willing or not; that's just wrong. In that sense, Stallman sticking up for his friend was probably not the greatest idea, but if he said she was coerced, and not actually willing, then it's wrong that he should lose his job for saying things he never said.
And yeah, sure, Stallman is a weirdo. Occasionally even a disgusting weirdo maybe (I remember a video where he seemed to pick something from his toes and put it in his mouth), and I recently read a description of events where he publicly embarrassed a woman for being present at a tech related event. (Edit: it seems he has a long history creepiness towards young women, including his students.) If you're gonna fire him, fire him for that, not for something he didn't even say in a private mailing list.
In general, I'm fine with weirdos. We need more of them, not less. Being a weirdo is no excuse to act like an asshole, but on its own it's no reason to ostracise someone.
But this issue? If the description from the article is correct, it seems based on a blatant lie.