The issue was that RMS did not conform to some ideology and so he was bullied. The fact that he is wrong or right about his opinions it's not even relevant. We have normalized ad hominem attacks, amplified through social networks. Reputation was everything in medieval science and we are moving in that direction.
Ad hominem would be using his misbehavior to attack, say, the FSF. Noting the fact he regularly made his female coworkers (and not only coworkers) uncomfortable is not an ad hominem - it's a direct criticism of his attitudes.
