it's a mental disorder in the context of you having wrong thoughts about children, not you being unable to function as a normal human being.
labeling it within the same category of stuff like autism and schizophrenia is just forgeted up, the only reason it's listed as a disorder is because it's out of the ordinary, not because it's a serious health issue.
it seems like you're lifting the terminology of "mental disorder" to a much higher severity level than it really is. a mental disorder doesn't have to be something life-destroying, it can be lots of things like mood disorders, anxiety disorders, etc. it's just a term to describe a kind of condition. (examples
https://psychcentral.com/disorders/ )
also autism and schizophrenia aren't really always that big a deal either. autism especially is an incredibly broad term, and there are varying degrees of severity for each patient of any psychological condition. heck, i know someone with schizoaffective disorder, it's not something you'd choose to have and it makes life harder, but it's not stopped them from acting like any other person in the slightest