If you were both under the age of consent, as is often the case, in many jurisdictions [0], neither of you were able to give consent, and your sex act was technically non-consensual on both sides. This is not just theoretical -- there are many cases of prosecutors charging consensual underage couples with statutory rape, or with child pornography charges for sexting a picture of themselves to their boyfriend/girlfriend, and often using these laws in unjust ways (e.g. charging only the black boyfriend with statutory rape, but not equally charging the white girlfriend).
Let's assume you and your first love grew up in California, had sex for the first time just days prior to your 18 birthdays (when you both became legal), and are now 30 and have been happily married for 10-years. By your definition, you both committed violent sexual assault, and I'd be correct to go around your workplace saying things like "oh zzzeek? you know he's committed violent sexual assault. Some sort of rape. I don't know the details, but just wanted you to know."
This is a contrived example, and I'm in no way equating this with Minsky or Epstein. I'm not defending either of their actions whatsoever. But I think that Stallman is correct that using words in this type of manner, deliberately ignoring such qualitative differences in degrees, is unfair. It doesn't matter what the legal or dictionary definition might be -- it's creating a misleading impression in someone else's mind as to what you are guilty of, rather than simply stating in clear terms what you did and letting that person decide for themselves how culpable or abhorrent you are.
[0] https://www.wklaw.com/sex-between-teenagers-can-lead-to-a-co...