Something that I think most folks in this thread are missing, that's hugely important to what actually happened here:
This was not an isolated incident.
If it were, I'd look at his comments and write it off as his usual tendency to jump on a minor point and derail a conversation with some totally pedantic technicallity, and I do think the thing he actually said in this case has been wildly mis-interpreted and overstated in many places (the bits about him defending Epstein are clearly untrue, and even the author of the blog post that went viral and set off the shitstorm has said so, and sent corrections to the publications she'd spoken to directly).
I even agree with his statement that, from a moral standpoint 17 vs. 18 isn't really that important -- we set arbitrary cutoffs for age of consent and it's not like there's a legal determination to be made re: Minsky anyway: he's dead.
So from that mailing list thread alone, it reads like a typical autism-spectrum dude missing the social context, making a pedantic point that people read too much into and take the wrong way, and getting himself in trouble. And this is an angle that would naturally draw my own sympathies toward him.
But Stallman is on-record as saying he thinks there's such a thing as "consentual pedophila", and given that context, I think folks can be forgiven for reading into his current statements.
Ultimately though, the bigger issue isn't even about anything that happened in the past few days. RMS has been behaving inappropriately in more serious ways for decades. There are many stories out there about him harassing and propositioning students, making wildly inappropriate remarks to women, and generally making a bad situation around gender and inclusiveness in tech worse. Everyone I've talked to who has known him in a non-trivial personal capacity has corroberated this. The fact that this email is the thing prompted a blog post that happened to go viral and got people to make a fuss about it is incidental.
Even at the FSF's own conferences, he's one of the more frequent violators of the safe space policies that the organizers have put in place. I think the first year the conference had an explicit safe space/anti-harassment policy, he was the only person who violated it (in this case it took the form of a sexualized joke during his closing keynote).
I kinda have the same somewhat fearful gut reaction to these kinds of episodes as a lot of geeky guys do. There's a post[1] out there (which I think originally I found through hacker news) that does a pretty good job of analyzing where that reaction is coming from, and why the fear isn't totally illegitimate, but the idea that this is just a mob picking on some misunderstood misfit is just not what's happening here. Folks have been lienient to the point of negligience with him up until now.
[1]: https://medium.com/@maradydd/when-nerds-collide-31895b01e68c