They're referring to the following argument in the queer community:
- Some people (mostly young people - people below the age of ~25) believe that being 'gay' or 'lesbian' is about gender (e.g. a woman attracted to a pre-op trans woman can still be a lesbian, but a woman attracted to a trans man wouldn't be). Others (mostly older people) believe that being 'gay' or 'lesbian' is about sex (e.g. a woman attracted to a pre-op trans woman is bi but a woman attracted to a trans man can be a lesbian).
Honestly, I think we should just have different terms for each. It's clear that there ARE large amounts of people attracted to (basically) either femininity or masculinity as opposed to bodies, so why don't we make a term for that just like we did for lesbians and gay men? That's what humans do.
The main thing I'm concerned about is how mean the young people are to those who don't agree. It doesn't impact me much, but I do worry about the messages young homosexuals are getting from their peers: There's a large conflation of being attracted to someone with moral approval which is...gross. Basically 'if you're not attracted to trans people, you're a transphobe.' Which isn't how any of this works, but teenagers listen to their peers because developmentally, that's what they need to do.
The person replying to you isn't correct that they want to 'change' the definition, though. It's more that we (the queer community) didn't bother nailing down which definition it was when the queer community was small enough that the issue rarely came up, but now it does and it turns out a lot of us disagree.
That's as neutral a run-down as I can give you. The person replying to you is on the 'it's sex based' side of the fence and I get the sense they're testing out whether they can discuss such things here, since a lot of queer/gay spaces online have very much Chosen A Side, and since the internet is full of young people and they have more time, it's mostly the young people's side.
