> at least one source that claims that he turned her down
We're not debating what happened: as far as I know, Minsky is presumed innocent until any potential judgements are delivered. What RMS was debating was not whether Minsky has done anything wrong, but whether he has been accused of doing so.
Minsky was accused of having sex with a girl who was being coerced at the time. Even if one wants to split hairs about Epstein being some kind of enforcer figure of said coercion, I'm pretty surprised that people would somehow believe this would nullify Minsky's alleged act being considered sexual assault?
He may not have done it. He is still only "accused". But the act he is accused of is inarguably assault.
It doesn't contradict what RMS is saying.
> The word "assault" presumes that he applied force [...] but the article says no such thing.
"He" here means Marvin Minksy and the part of the article you cited doesn't imply that Minsky forced the victim.
Also I haven't seen sources that claim that the victim had sex with Minsky and seen at least one source that claims that he turned her down [0].
[0]: http://archive.is/nZIjt#selection-269.94-269.136