No "mob justice" happened here. No women came forward and said RMS "hit on them" or whatever. RMS faced criticism for comments which justified rape and were close to victim blaming, and willingly resigned from his position at the FSF because of it. A position I personally believe he could have kept had he decided not to resign (and the fact that he is able to return to it so soon after leaving suggests I am correct).
Edit: I think that several people are placing too much importance on the "willingly resigned" part of my comment downthread. If you believe that RMS was forced out and he had no choice in the matter (i.e. it was "resign or get fired"), then feel free to replace the words "willingly resigned" with "was fired" in my comment (and ignore the last sentence in that paragraph), the point being made still stands.