It is if the distinction between prepubescent children and postpubescent children is relevant, which certainly is the case in our current system of laws.
Furthermore, failing to observe such distinctions makes every single term that describes any kind of activity that some people don't like--pedophile, rapist, etc.--all equivalent; they all just mean "bad person". But that makes it impossible to have a useful conversation at all, because "bad person" is not a useful category if you're trying to figure out what to do about such people. You have to look at the specifics. If you refuse to look at the specifics, then you're not helping to do anything about the problem; you're just virtue signaling. "I think all of these people are just bad!" Okay, got it, thanks for sharing.
A couple of days ago I attended a talk he gave at the Seattle Public Library and he did the "well technically..." routine to an audience member who claimed to be a fan of free software ("It's strange to say you're a fan of freedom [...]" or something to that effect.) He also did it in response to several other topics, but that one stood out to me.
I don't wish to pathologize aberrant social behavior since that could probably be turned back against me pretty easily, but if one were so inclined I think classifying Stallman would be pretty easy... Pedantry and lack of tact is a trait I've seen before.
It's not that one is worse than the other, it's just that they're quite different situations. I don't know exactly in which category Epstein falls because I haven't been following this whole ordeal too closely, so I'm not making any claims about that.
And this ... as if the distinction between prepubescent child rape and postpubescent child rape is at all relevant enough to mention.