I think that's factually accurate. He's not a professor of sexology and (to my knowledge) has never pursued any formal study of the topic.
Not everybody needs to be Dr. Ruth, but in some sense, Stallman going on about sex topics when he's not is as much a problem as Sagan once going on about the "reptile brain" without considering how much of the neuroscience he was contemporary to had already disproved that hypothesis.
If you're going to have strong opinions on something and want to maintain your credibility in general, at least find a trustworthy and informed advisor on the topic.
It's not a question of sexology, it's a question of ethics. I doubt that any of his critics are professors of sexology as well, people are arguing on moral ground here.
Many of issues people are attacking him on, are not issues in my country. I don't see many fellow Europeans bothering what he said, it's American moral issue totally.
Not everybody needs to be Dr. Ruth, but in some sense, Stallman going on about sex topics when he's not is as much a problem as Sagan once going on about the "reptile brain" without considering how much of the neuroscience he was contemporary to had already disproved that hypothesis.
If you're going to have strong opinions on something and want to maintain your credibility in general, at least find a trustworthy and informed advisor on the topic.