Because that's what it's about: he said, "But is it really?" — literally, in fact — about something which, for legal purposes, his opinion is irrelevant. To wit:
> Does it really? I think it is morally absurd to define "rape" in a way that depends on minor details such as which country it was in or whether the victim was 18 years old or 17.
Stallman said that. He went there. He quibbled over whether something constituted rape, as if the Virgin Islands cares one whit what rms thinks of their laws. That's where he screwed up, and people in the thread said so at the time, too. So people now can try to make this shit-show about his being quoted out of context about "entirely willing" — which, again, it was — as much as they want, but that just won't make it so.
This is entirely about Stallman having quibbled over rape, not whether he was selectively quoted in the course of quibbling over rape.
EDIT: Phrasing