full offense but if your only identity you have public is “asexual” we’re all gonna assume you’re cishet because actual LGBT people don’t have to pretend to be special
Or alternatively, people have a right to identify how they choose, and prioritise and share their identity how they choose. Often, especially for trans people, not publicly sharing aspects of their identity is a matter of safety, and assuming cis as the default is harmful. By policing the identities of other people without knowing anything about their lives or identities, you are behaving no better than any homophobe who makes assumptions about someone because they dare to be openly gay.
I say this because your premise (that a sexuality is a lifestyle choice designed to threaten your pre-established norms), your line of reasoning (that people who identify with that sexuality are hence a threat to you) and your conclusion (that hence people labelling themselves with that sexuality are clearly doing so to inconvenience or distress you) are pulled directly from homophobic rhetoric. No, this statement is not direct homophobia (though it is indirectly), but your rhetorical structure is literally copied and pasted from homophobes.
The logical conclusion of your argument is that LGBT people (curious that you don’t include Q, I, A, P, N, or +…) are the arbiters of who is reasonably not cis or straight, and that anyone who seeks to self identify without first being approved bt the LG gatekeepers is merely a special snowflake tossing themself into a world they can’t possibly understand. Not only is that infantilising (a particular facet of asexual oppression), but it is also directly lifted from the rhetorical premise and conclusion of conservatives.
Also, by enforcing the idea that “cishet” is the default from which LGBTQIAPN+ people deviate, you are propping up the cisheteropatriarchy which oppresses us. Respectability politics and confining the community to the most easily defined and best known identities may seem like a good way to get a leg up against the rest of us, and be the lap dog of our oppressors who they use to keep the rest of us down. But the reality is true liberation can only come when we all band together to change society and remove all cisheteropatriarchal structures, including the expectation that we all be allosexual or alloromantic.
Essentially, this gatekeeping and purity culture for the LGBT community is fundamentalist christian conservatism in a gay hat, and I’m sick to the back teeth of it. We’re here, We’re queer and we need to stick together damn it so stop driving wedges into your own community. We face enough hate from the rest of the world. Learn queer history, and stop making our community a battle ground so you can feel superior.