Except, of course, when he talked about gender identity, the transgender "agenda", how he refers to the gender of other people, and his construction of what somebody "really" is.
Thanks, I'm already familiar. (I'm not clear that you are, though, so unless you start being more explicit about your point, I'm done after this.) When he talks about how he refers to people, then we're already in the land of gender. Biological sex is something he can't directly perceive. He is basically saying that he wants to act as if gender is always exactly equivalent to biological sex. His post is basically arguing for a simplistic and essentialist notion of gender. Thus his opposition to the transgender "agenda".
This user quite clearly refers to people in regards to their sex, rather than their gender. You're making the mistake of assuming that he cares about gender, when sex is what he uses for his classification of male or female.
If he is classifying them as male and female and treating them as such, then both parts involve gender.
The first half involves judging people by appearance; unless he's running DNA tests, ultrasounds, and fondling everybody he meets before he uses a pronoun, then he his judging at least partly by how they present. That's gender.
The latter half, how he treats people based on his gender-presentation-mediated perceptions of sex, is pure gender, because there we're entirely out of the realm of biology and clearly into the social side of gender roles.
I understand why he (and apparently you) would like it to be simpler. It's more convenient for him if everybody goes around hiding the complexity for him so he doesn't have to have a more accurate view of the world. But it's bunk. Pretending that it's "just" sex he's talking about is part of the way he hides, presumably also from himself, that it's bunk.
