Most of these categories exist as actual concrete things. Genders are a thing that exists, biologically. Sexual preference is a thing that exists. And if you want to identify as a different gender than your genes, that’s cool too.
But defining yourself as a word that literally did not exist until YOU made it up? It just doesn’t mean anything. It’s a use of language which is nonsensical, in that it doesn’t convey any meaning.
Like, if you ask me my gender and I say, “I’m sedkjkjnfkse!” that means nothing. It’s not a word in the generally understood vocabulary of society. For all intents and purposes, it’s just “N/A”.