The argument is that often renegade and maverick thinkers are deeply deeply flawed on an individual level and would do stuff like that. This doesn't really fit well into the "progress category" of civil rights, it's more about advances in technology.
TBH I don't know jack about Richard Stallman, but my understanding is he played a huge role in developing the idea of free software which has had enormous benefit to the world in general.
The question is does the benefit the ideas and works of Richard Stallman have brought warrant the personal costs he has imposed on many people around him? And in the future, are the potential personal costs another Richard Stallman would bring worth the advances they could bring in another area?
To put it even more bluntly, will it be possible to have the types of significant progress we desire in technology or what area, while excluding people who on a more personal level we find deeply problematic? Can the best parts of a Richard Stallman or Steve Jobs be separated from the worst parts? Can we in a sense "sanitise" progress so that only people we find socially acceptable are the ones who will do it? What if the people who will do most for humanity's collective properity are (a) assholes (b) unprofessional, and (c) never the shut the hell up about stuff they know nothing about?
I don't have an answer here, but it is going to be an issue worth thinking about going into the future.