The problem with the use of "sexual assault" in this context is not that most people would consider what seems to have happened to be a "sexual assault" by Minsky, while Stallman does not; the problem is that, on one hand, almost anyone familiar with the facts as I stated them above would agree that there's no reason to believe Minsky sexually assaulted anybody; and, on the other, almost anyone would agree that Virginia Giuffre was the victim of something far worse than sexual assault: she was enslaved and repeatedly raped. There's just no reason to suspect that Minsky was the culprit. Many reasonable people condemned Stallman's words not because they disagreed with him on his use of terms but because they had false beliefs; for example, many of them believed Stallman was arguing against believing something that Virginia Giuffre had said.

If "autistic well-actuallyism" is the only way to rebut entirely groundless accusations of sexual assault, then I guess society needs a great deal more autistic well-actuallyism, because widely-believed baseless accusations of serious crimes are very destructive to society; they were the major excuse for lynchings, for example. Rather than "autistic well-actuallyism" I usually use terms like "due process", "justice", and "rationality", but if you want to call those "autistic well-actuallyism", that's up to you.

It's also factually false to claim that mainstream society considers any sexual activity between an adult and a 17-year-old to be assault. While my wife did suffer social ostracism due to our relationship, almost nobody believes that she "assaulted" me. That is far from a mainstream belief. Are you saying you think she did?

I've already explained what happened in the Gosling case in https://news.ycombinator.com/item?id=21252185, but I'll summarize again here. Gosling was just lying about what happened. After Stallman had been maintaining EMACS for five years, Gosling wrote a clone of it for Unix, incorporating code from some other people. He gave permission to one of those people, Fen Labalme, to redistribute his modified version of it. Stallman wanted a Unix Emacs, so he started working on Labalme's version of Gosling's clone, but had to replace most of it. When he published his version, Gosling had apparently changed his mind about the redistribution permission, so he threatened legal action. Stallman at first responded by protesting that Gosling had no right to attempt to retroactively revoke his permission (particularly when Gosling was profiting by selling his Emacs clone, including the contributions of Labalme and others, to Unipress), but after a short time, he replaced the remaining pieces of Gosling's code to eliminate the issue. This all happened within a few weeks in 1985. As far as I've been able to find out, the Unipress lawsuit Gosling referred to never happened.

Gosling doesn't, I guess, "feel very much stolen-from". He tried to make a buck by copying Stallman's work and sending legal threats to Stallman about it. This led to Stallman publicly vilifying him; that's why he hates Stallman. Most people wouldn't respond to hating somebody by lying about them to damage their reputation, but that's what Gosling did.