My biggest question for you is: why?
If somebody says they feel disconnected from being human, the response shouldn’t instantly be “you’re actually non-human.” That can push vulnerable people further away from reality and deeper into unhealthy coping mechanisms. A lot of younger people especially are still figuring themselves out, and spending years convincing yourself you’re secretly an animal or fictional being can seriously affect your self-image and emotional development.
You say this with a lot of confidence; do you have any actual evidence this is the case? Why do you think being nonhuman inherently "fantasy" and an "unhealthy coping mechanism"? Why do you think that being nonhuman/fictionkin affects "emotional development"? I could take some pretty educated guesses and respond to those, but I'd rather hear your explanations from you.
I also think a lot of this comes from escapism. The world is stressful, people feel isolated, and fantasy identities can feel comforting because they offer a sense of uniqueness, belonging, and control.
A) What makes nonhumanity any more of a "fantasy identity" than any other?
B) Yes, otherkin and fictionkin often do feel isolated from the people around them - because they are having a vastly different life experience than the average person. For many, finding the alterhuman community is a breath of relief, of "Oh, there's words for what I've been experiencing my whole life" - and I don't mean the isolation feeling, I mean things like instincts that don't match the human template, phantom limbs, a self-image not matching up, etc. (This is true even for many who don't feel particularly isolated from their peers, myself included.) There's a reason that the otherkin community offers a sense of belonging, though I would disagree that it inherently offers any sense of "uniqueness" or control.
What worries me most is that encouraging every unusual identity claim without skepticism can prevent people from getting actual help. If someone is deeply distressed, disconnected from themselves, or obsessively identifying as something non-human, they deserve compassion and support from real people, not internet validation. Therapy, self-reflection, social connection, and building confidence in yourself as a human being are healthier long-term solutions than disappearing further into fantasy identities.
I think you're making a bit of a false equivalence here - you're assuming that every nonhuman, or at least the majority of nonhumans, are "deeply distressed, disconnected from themselves, or obsessively identifying as non-human" (emphasis mine). That's... frankly, not really true in my experience - to use myself as an example again, I stand as a counterpoint to all of that; there's no distress or disconnection associated with my nonhumanity, and I think calling me "obsessive" about it is just plain inaccurate. Furthermore, for many, it's denying their nonhumanity that causes them to feel distress and dissociation. Trying to repress your nonhumanity is, generally speaking, Bad For You; we've seen this over and over again in this community. If species dysphoria is an issue, much like gender dysphoria, the answer is not trying to repress it - it's finding ways to express your species (or gender) that provides relief from the dysphoria.
Overall, you seem to be making a few false assumptions, though correct me if I'm misunderstanding you on any of them -
Nonhumanity is absurd to you, and therefore isn't a "real" identity
Following (1), "fantasy identities" are an indication of inherent distress and disorder
When nonhumans experience distress, dissociation, dysphoria, depression, etc., the problem is that they are nonhuman and that should be treated like a mental illness (as opposed to the possibility that, again much like being transgender, the problem is that society does not accept them and the answer is acceptance and self-expression - that being nonhuman is not inherently distressing, it's the inability to express it that creates distress)
I do agree with you that if someone is experiencing significant distress and dissociation, they deserve help and should probably get professional advice if it's available to them - and you may find it interesting that many nonhumans already do. I have personally known many nonhumans who are or have been in therapy for various issues - and their nonhumanity is rarely treated as an inherent problem, in my experience, even when treating species dysphoria and similarly related issues.
