Idk. If someone can pinpoint a single cause, it is binary. Not that I think that's possible: the human mind is so poorly understood, a real cause-effect relationship is scifi.
> some people are barely distracted by loud noises ...
It's not an argument for a non-binary classification. The whole point is that that a symptom, even a group of symptoms, doesn't define autism. Sensitivity to noise is just one of those things that some group has managed to be associated with autism.
Its definition has been expanded significantly. If it continues, there'll be two types of people: autists and psychopaths.
Yes, the problem isn't that the definition isn't 100% formal. If "autism" meant "unusually sensitive to loud noise" (and presumably other symptoms get new labels) that would be reasonable. But it seems to mean "unusually sensitive to something OR unusually methodical OR unusually bad at reading emotions OR unusually affected by other's emotions OR ... ", and almost nobody has every symptom, but two people may have completely different symptoms while a third person has some from each.
If you just have one of the symptoms you shouldn't be diagnosed with autism.
I think a lot of people miss that the changes that combined a ton of stuff into autism was because we had a ton of different disorders that had super similar treatment plans, but it could cause issues when your doctor didn't know all of the related disorders to be able to know to try different treatment plans.
The combining was an acknowledgement that we don't know what causes these combinations of symptoms to occur but they seem to be related when certain combinations of them occur and these treatments can work to lessen the impact on the person experiencing it.
> some people are barely distracted by loud noises ...
It's not an argument for a non-binary classification. The whole point is that that a symptom, even a group of symptoms, doesn't define autism. Sensitivity to noise is just one of those things that some group has managed to be associated with autism.
Its definition has been expanded significantly. If it continues, there'll be two types of people: autists and psychopaths.