Sidestepping the larger thread for multiple reasons: if there are people who identify as dragons, and they do human things anyway, I don’t care. If there are people who identify as dragons, and they want to eat virgins, I want to stop them for the same reason I want to stop humans from eating virgins. I don’t have separate rules for humans and dragons.
I agree with this on its face.
But here's the thing: certain quirks indicate a high likelihood of wanting to do something that is harmful. Someone believing that they are a dragon, it would seem, is much more likely to have the delusion that they can fly, which comes with obvious hazards, or that when they breathe on raw meat they're cooking it (or the eating-virgins thing you mentioned, I suppose). That is, unless they believe they're actually a dragon but somehow live exactly as a human, which is incoherent unless it's a more abstract spiritual sort of belief (which a lot of the time I suppose is the case for otherkin), to which I have about the same attitude as I do to most religious beliefs which is standing for tolerance of them but to some degree regretting their prevalence and certainly bristling if I'm required to give positive affirmation of them.
(Compare to Sam Harris and others arguing, in the context of free will and ethics -type discussions, that character/intentions/motivations matter when we compute moral judgments, because while in themselves they don't decrease utility, they are indicators of whether a person is likely to do a utility-decreasing thing. Also compare to the general verdict around Chickengate -- I'm referring to an explosion in rat Tumblr discourse instigated by Nostalgebraist during my earliest years here (can't remember if you were also around) about how we should judge someone knowing that they f***ed a dead chicken, the idea being that while the act doesn't directly do harm, it indicates something about the person doing it that suggests they might do harm in other ways.)
A variation on the above: even if for most individuals an untrue or incoherent belief isn't leading them to do harm, I (and I think most other people) generally see beliefs in falsehoods as a Bad Thing compared to beliefs in truths and want to increase the latter at the expense of the former within society.
These considerations, applied to someone thinking they're a dragon or an attack helicopter or a raccoon, mostly don't map very well to transgender people, though.
