One of the few 'sentences' of Japanese I actually know is "Watashi wa neko desu, nyo..." (Well, technically, it's the bit before the comma, after that it's apparently onomatopoeic, and I can't check I've got the 'spelling' correct.)
I'd say that "I define my gender as a <helicopter/whatever>" is often bad-faith absurdism, by those that don't believe that "◇gender≠sex" and decide to go the "by supporting gay marriage, you'll have people marrying animals/buildings next" contrary argumentation.
Separately, there is roleplay (everything from Furoticism to LARP), which is "honest deviation" across any or all boundaries (which may or may not involve some genuine personal dysphoria, but one can't assume that either).
The issue of not being able to label yourself with standard binary genders
or binary-derived alternatives (not this one/the other/various proportions of both/neither/varying day-to-day or more) and deciding that the nature of a cat encompasses what you're feeling does not mean you're genetically a cat, but neither does what you feel about your gender have to match your genetic gender (and/or your physical phenotype, which can be different again).
I'd honestly consider "my gender is pony" as more in the second category, perhaps the third. I would maybe query more detail, given the opportunity, especially as actual ponies would not thenselves be single-gendered (though maybe "My Little" ones are?), and perhaps weed out the first-category type by paying attention to the context it's being put into.
But, so long as no harm happens, I don't think it's my business in what ways a person decides to shape their life. And probably the harms I need to be most concerned about are those coming directly from the "absolutely not"ists who can't even remain slightly bemused by it all but insist on 'correcting' the perceived situation.
(This was not in direct response to Strongpoint's earlier post, and indeed was just ninjaed by their latest one (wgich somehow managaged to step on some of the same stepping stones of conversation, although maybe with a different foot!) so don't take this as a response to that in any way at all. It was just a ramble around the theme to perhaps try to place my personal philosophy in context.)
[edit: Had to post first, to properly check, but I came up with the "<helicopter/whatever>" reference entirely without any mention in the recent thread. Only to find that the message above mentioning it. Which all goes to show that the (discredited) "I identify as a helicopter" meme, which I'm sure I've seen 'hovering' around such discussions for three decades (possibly more) is a rare but perrenial favourite. Perhaps even invoking some gender-discussion equivalent to Godwin's law, indicating that the conversation should now be considered over as unlikely to resolve well now that helicopters are mentioned.
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