IIRC, last year Dawkins read Kathleen Stock's book Material Girls, the publication of which resulted in her being forced to leave her position as a professor at Sussex University. Dawkins tweeted that he was reading it and found it well researched and presented. Obviously he got a twitter pile on for that. The next day he tweeted that he was attacked while driving his car and his car damaged. It definitely seemed like it was implied that he suspected the two were connected. Even if they weren't he was shaken enough by the response to him saying a book was well researched that an unpleasant real life event felt linked.

I think up to that point he hadn't felt like this was an issue that seemed that important. Similar to Prof Robert Winston, he obviously knew that there were two sexes but mostly assumed that the handful of people wanting to live as the opposite could just be treated with quiet politeness. Which is honestly where most people were and many still are. But once you raise your head up and make an innocent point that is obvious common sense that you assume won't be disagreed with or you notice that some people are being hounded for doing that, that you suddenly realise that this has gotten serious and scary while you weren't paying attention.