Here's the text of that tweet:
Dress however you please.
Call yourself whatever you like.
Sleep with any consenting adult who’ll have you.
Live your best life in peace and security.
But force women out of their jobs for stating that sex is real? #IStandWithMaya #ThisIsNotADrill
The argument is over the sacking of Maya Forstater, who lost her job at the Centre for Global Development for another tweet (among others, I think) that said: What I am so surprised at is that smart people who I admire, who are absolutely pro-science in other areas, and champion human rights & womens rights are tying themselves in knots to avoid saying the truth that men cannot change into women (because that might hurt mens feelings)
To quote from thehill.com
Forstater challenged her termination in court and lost. The judge called her views “absolutist” when referring to someone “by the sex she considered appropriate even if it violates their dignity and/or creates an intimidating, hostile, degrading, humiliating or offensive environment,” The Guardian reported.
Several LGBTQ groups attacked Rowling for backing Forstater, including the Human Rights Campaign, which tweeted, “Trans women are women. Trans men are men. Non-binary people are non-binary. CC: JK Rowling.”
What seems to be of particular significance is that a lot of people who find themselves a part of the LGBTQ+ community feel somehow connected to the outsider-ness of the characters in Harry Potter, the fantasy, the otherness, and so JK Rowling - through the magical world that she created - is their champion. So many young people have lived their lives so far with Harry Potter and his world as a part of theirs, perhaps a really formative part of theirs, that to find its creator disagreeing with them on the subject of those whose gender doesn't match their genitals.
In the first instance, it's not entirely clear that that's what she did. Rowling seems to be saying that sex, which in this interpretation is more-or-less a function of the aforementioned genitals, is a real phenomenon distinct from anything to do with gender. The conflation of biological sex and sociological gender is old and, for some, unlikely to ever be disentangled. If I read it right, Rowling is saying that being biologically female is a necessary condition of being a woman, and that woman-ness is tied to biological femaleness. Whether that involves any of the tropes of the feminine gender is a moot point, because being a woman isn't about gender (in this interpretation).
On the other end of the scale are those who - as the Human Rights Campaign tweeted as quoted above - state simply that trans women are women (and trans men are men). That puts the definition of 'man' and 'woman' in the realm of social, not biological, matters. You choose what you are, and your biological sex is more-or-less irrelevant, except perhaps in so far as it drives a person in a particular direction with regards to their gender.
This is one of those philosophical fights that exist because the two sides don't agree on the rules. The perspective which says that a (biological) man cannot become a woman, regardless of self-declaration (and which is sometimes characterised as or possibly conflated with radical feminism, and is certainly a position expressed by many radical feminists), rests on the prior assumption that man-ness and woman-ness are biological (only). The opposing position, that a person's choice rather than their genitals determines who that person is, and in particular whether that person is a man or a woman, rests on the opposite assumption, that man-ness and woman-ness are not matters simply of biological sex.
It's instructive to listen to young people's voices in this matter. Almost without exception, the clever, caring ones, the ones who have put some thought into their position, those ones who strike you in conversation as grown up are very much in the second camp, putting people's choices at the fore. Their world is one, as far as I can tell, that is less connected to the kind of feminism I mentioned, perhaps even rejecting it as outdated. That is perhaps why JK Rowling's is such a significant contribution to the argument, because it goes against the thoughts of her audience.
I have no answers to this question, though. I am not well-informed on gender studies, or on biological sex. But I will bring up something that I encountered a long time ago. I met a man - who defined himself as such at the point I met him - who had, for some time, been trying to live as a woman. Twenty years or so ago, that was not something that was particularly the subject of public debate, not something that was in the foreground of the conscience of even young people. We were in the throes of ridding ourselves of the established racism and homophobia of our parents' generation, and their parents. In any case, this person, who might have been a bit happier had he been able to make that transition and be she instead, described being bullied, abused and attacked as a result of that set of choices. That, to me, seems to be what matters. You do what you can to be kind to people, and you try to be a positive influence on those around you. Does it truly matter whether this person I met was a man or a woman? Those are words, labels at best. What he wanted was to live as a woman, whatever that is.
When to the sessions of sweet silent thought