I'm going to put "treatment" in huge quotes. Do these people need treatment or do they need society to stop bothering them and accept them the way they are?
What does any of that have to do with society bothering or accepting me?
The idea that there isn't such a thing as a condition causing malfunctions in mental processes, and that all such things are just differences in preferences and such that merely need to be "accepted", doesn't make a lot of sense to me. If someone gets brain damage which damages say Wernicke's area, and causing Wernicke's aphasia. It would be quite silly to say that this isn't a problem or damage which could make sense to treat.
I see no reason that this should change when the differences are more subtle and such.
Now, that being said, I do think it makes sense to basically always defer to the person's own evaluation of whether they need treatment. If someone claims they don't need or want treatment, forcing them to receive "treatment" is, uh, in almost all possible situations, very bad? (note : this doesn't mean "in almost all situations in which this actually ends up happening.". I don't know about those cases. But the danger of like, classifying political opponents as being mentally ill and as needing treatment, is such a terrible danger, that norms should forbid anything within a very large conceptual distance from it.)