It's not about what I believe, it's about what we already know. Computing is old enough now that you don't need to be some kind of mad prophet to know things about the future, because you can just look at how things have played out already.
More to the point though.. at the beginning at least, Stallman was a respected hacker and not just some random person pushing politics on a community he was barely involved with. It's gotta be that way I think, anyone who's not a respected AI/ML insider won't get far