That was me. I would point out that that tweet is from the RDFRS, his society, not him. Although it bears his name its its own organization with staff and he won't be the one tweeting from that account. The phrasing doesn't sound like his writing and as you've pointed out, he's also endorsed a GC book. So I'd put that down as someone made a poor choice in hiring at the Foundation rather than suggesting anything about Dawkins' views.

My take on this tweet is look at it at face value:

I do not intend to disparage trans people. I see that my academic “Discuss” question has been misconstrued as such and I deplore this.

He clearly didn't intend to, and he's far from the first person to get attacked for asking questions and trying to have a discussion.

It was also not my intent to ally in any way with Republican bigots in US now exploiting this issue.

This is the narrative that's presented, headlines about "Republican Anti-Trans Bills" and such. Its a common TRA attack - "you're just conservative/bigots/etc", even though that isn't the intent of GC people. So its a true statement.

What it suggests to me is that he doesn't know about GC as a 'thing'. He's baffled/bemused by the hostility of the response to his first tweet, and trying to issue reassurances that his question didn't come from a place of bigotry, assuming - as many have before - that honest questions will be well received.

I'd almost describe as like the moment when someone is pre-Peak Trans, except without ever having been acquainted with the Trans side first.

Its obviously unfortunate that that's what he chose to say. But I'd have to put it down to simply ignorance of the situation, not malice or having been taking in by unscientific arguments.