My son was a heroin addict for about two years and my daughter would always say "he should just quit." She didn't believe in addiction. She believed a person could will themselves out of an addiction. There are many people out there who will classify and judge things without having any knowledge or understanding of something. You may encounter some of those people. Addicts can't just will themselves to quit, if they could do that there would be no need for interventions or rehab clinics.

It's the same with your symptoms. I don't believe a person with autism is an expert on autism. It's a spectrum thing, so each person experiences a spectrum of symptoms. That means not one single person with autism is an expert on autism. And there isn't a single doctor on the planet that is an expert on autism either. No one is.

You know your symptoms the best, so you need to stop caring about defending what you believe to be true or not true. It doesn't matter if it's true for them, it only matters if it's true for you. This empowers you to take what you know and use it to empower yourself.

Whether you have autism or not is not the point though, is it? It seems you are looking to somehow improve your life. Part of that is to stop caring what these other people are trying (intentionally or not) to put in your head. Anyone who is suffering from behaviour that they themselves view as either harmful or holding them back can alter some of those behaviours with mindfulness (a form of behaviour modification). And yes, this also works for autistic people, because they too have minds.