Not looking to burst any bubbles here but i think he was one of ‘them’.

(Copied from elsewhere - not my text below):

Oh, Heinlein was worse than that.

He was a close personal friend of notorious pedophile Walter Breen, and in the early 1960s when stories of Breen raping little boys started coming out,

https://fanlore.org/wiki/Breendoggle

Heinlein sided with Breen, cutting off many ties in the science fiction community.

As Heinlein wrote to Marion Zimmer Bradley, herself a child rapist and Breen's wife: "The fan nuisance we were subjected to was nothing like as nasty as the horrible things that were done to you two but it was bad enough that we could get nothing else done during the weeks it went on and utterly spoiled what should have been a pleasant, happy winter. But it resulted in a decision which has made our life much pleasanter already…We have cut off all contact with organized fandom. I regret that we will miss meeting some worthwhile people in the future as the result of this decision. But the percentage of poisonous jerks in the ranks of fans makes the price too high; we’ll find our friends elsewhere."

(source: https://nevalalee.wordpress.com/tag/robert-a-heinlein/)

Robert Heinlein was a visionary, that's for sure. Example: In his book "The Moon Is A Harsh Mistress" (1966 sci-fi) he predicted the rise of AI and self-aware machines. He was also a revolutionary, as depicted in that same book.