It is a different way of thinking generally but there are aspects of it that are truly a disability like having poor spatial awareness.
The reason it is thought of as a disorder is it is disabling in a neurotypically driven world. For example part of social interactions often involves lying. If you can't help but be too honest then obviously you're going to find it to be a disability that you can't lie well. But in this case it shouldn't be because people should really work on being more honest.