Treating "different things differently"

"the truth is that many lesbians and gay men are quite attached to the concept of sex as a natural, biological, material thing. Yes, we are very well aware that sex can be expressed in many different ways. A drag queen and a rugby player are both biologically men, with different expressions of gender. Indeed, a drag queen can also be a rugby player and express his gender identity in a variety of ways, depending on time and place. But he is still a man. . . .  Transgender people pose no threat to us, and the vast majority of gay men and lesbians wholeheartedly support protections for transgender people. But transgenderist ideology — including postmodern conceptions of sex and gender — is indeed a threat to homosexuality, because it is a threat to biological sex as a concept.
     "And so it is not transphobic for a gay man not to be attracted to a trans man. It is close to definitional. The core of the traditional gay claim is that there is indeed a very big difference between male and female, that the difference matters, and without it, homosexuality would make no sense at all. If it’s all a free and fluid nonbinary choice of gender and sexual partners, a choice to have sex exclusively with the same sex would not be an expression of our identity, but a form of sexist bigotry, would it not?"

     Andrew Sullivan, "The nature of sex," "Interesting times," "Intelligencer," New York, 1 February 2019.  Has Sullivan grappled elsewhere with what the gay/lesbian and the transgender identities would seem to have in common, though?