I had a look at this link from the twitter thread.
freethoughtblogs.com/pharyngula/2018/10/13/why-i-banned-andy-lewis-maria-maclachlan-and-alan-henness/
It's an astonishing rant from someone who claims to be a developmental biologist. His grasp of English is somewhat poor though.
I also don’t accept the automatic equating of “female” with “woman”, of confusing sex with gender.
He is presumably using a different definition of "woman" from that found in most dictionaries: adult female human. Of course we equate "female" and "woman", because all women are female, and all adult female humans are women. He presumably thinks that some women are male - which I suppose you would if you think TWAW. He seems to think that understanding a dictionary definition is confusing sex with gender.
Then: The presence or absence of a penis is possibly the worst gender signal ever, because we keep those hidden in almost all of our social interactions. I’d have to be really close, very intimate friends with a woman before she’d show me her penis.
I'd have thought a developmental biologist would be aware that women don't have penises.
That this process is strongly canalized developmentally to produce a majority of two reproductive types does not mean that variation is excluded, or that we should simply ignore or discriminate against anyone who differs. Biology doesn’t say what you claim it says, and it’s extremely obnoxious to claim the authority of science for your bigotry.
I presume he is referring to DSDs here. What on earth does that have to do with the scientifically accurate statement that people can't change sex?
I’m not even getting into gender. That’s the domain of psychologists and sociologists, and to even pretend that human beings emerge from the complexity of biological sex determination to then find a binary simplicity and clarity in psychology and culture is ludicrous. The only reality behind that is that there exist some gatekeepers who are deeply committed to the idea of there being only two allowed types of people, and who try desperately to enforce their narrow preconceptions by harassing people at transgender events or by trolling blogs. Or, I suppose, in some societies or in history, setting the deviants on fire.
Is anyone actually saying that people who present differently and don't conform to gender norms should be harassed or set on fire? If we were saying that, many of us would have to start by doing this to ourselves. He presumably has no idea what the people who he calls 'T**Fs' stand for.
The whole is like that: the TERFs interject their standard bad arguments, equating sex and gender, insisting that transgender individuals believe they have gametes corresponding to their professed gender, suggesting that transgender women are trying to violently oppress “True” Women, bringing up anecdotes of criminals who dressed as women, etc., etc., etc.
We are not the ones who equate sex and gender. We are very much aware of the distinction. He seems a little confused about it though.