Okay there are like three things wrong with what you just said.
1: Sure, maybe neurodivergency is linked to therianthropy, but that doesn't make it "abnormal". It's fine to have Autism or ADHD or something like that.
2. I DIDN'T NEED YOUR HOMOPHOBIC OPINION, YOU TRASHFACE. I don't even know why I'm still here, you're probably one of the most bigoted people I've interacted with.
3. Humans are animals, scientifically.
4. Don't ever speak to me again, you bigot.
Also, about therianthropy being seen as a mental illness-it's not. But it might be linked to neurodivergent occurrences/experiences. That doesn't make it any less valid though, and that doesn't mean it hurts somebody to identify in that way.
Dude. Who cares if someone identifies as an animal. It's actually not hurting them, for your information. And if your just trying to "help people understand" WHY are you doing so in a way that makes you seem like a jerk? And just because it doesn't fit in with your idea of things being "natural" doesn't mean you can hate on it and try to extinguish it. Like, people say being gay isn't "natural", but there actually isn't a "natural" standard for a human couple, and animals in the wild can be homosexual. So there.