I mean, his defense was of Minsky, not Epstein. RMS believes that Minsky likely wasn't aware of of either her age nor the coercion so Minsky could hardly be blamed for not knowing. I haven't followed this too closely (except on HN) but I think that incident also predated Epstein's first trial (conviction?).

I suspect (and really really hope) RMS wouldn't have such a defense for Epstein himself.