I agree with this, but I do think that there is a genuine debate to had about:
1. Whether people of different sexes ever ought to be treated differently (and if so, in which circumstances).
2. Whether people of different gender identities ever ought to be treated differently (and if so, in which circumstances).
My own view is that in the vast majority of cases we shouldn't be treating people differently on the basis of either sex or gender identity, and that identity-based gender and sex-based gender are about as bad as each other!
1. Whether people of different sexes ever ought to be treated differently (and if so, in which circumstances).
2. Whether people of different gender identities ever ought to be treated differently (and if so, in which circumstances).
My own view is that in the vast majority of cases we shouldn't be treating people differently on the basis of either sex or gender identity, and that identity-based gender and sex-based gender are about as bad as each other!