From another comment of mine, the specific relevant passage is on page 7. Copied verbatim - line with a '>' is Stallman quoting another e-mail in the thread.
"""
> Giuffre was 17 at the time; this makes it __rape__ in the Virgin Islands.
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.
I think the existence of a dispute about that supports my point that the term "sexual assault" is slippery, so we ought to use more concrete terms when accusing anyone.
His argument in this specific email- as I read it- was a variant of "Your Honor, I had no idea she wasn't willing and 18!" ie that Minsky didn't know and must therefore have been blameless.
I think it's an immoral argument too- Minsky should have known something was going on, and would be culpable. And it's very possible he did know.
But paired with RMS' prior pedophilia apologia, the combination is horrendous.