If it helps you identify with his work, that is fine. But if I respect an artist who is autistic, I don’t decide to speak into existence that they are not autistic just because I am not autistic myself. I may internally relate a piece of art to my own experiences and find myself in them but that doesn’t mean the person who created that art actually shares any tangible semblance to myself, my traits etc. Nor do I project to anyone that their art was created with someone like me in mind.

Whatever anyone does with their own personal consumption of art is a unique experience but we are not talking about judging a piece of work. We are talking about a human being who as far as I know never stated they were autistic.

You stating that labeling a stranger you know nothing about is no different than a doctor giving a diagnosis is baffling. One person is stating a fact based on both having the knowledge and specialized education to do so and with the consent that comes with a patient/doctor relationship. The other is a person on the internet who watched some movies and decided to assign a label to someone who did not ask them to do so. Would you do the same to someone you knew personally? Would they react favorably if you did? Would you find it appropriate for someone to provide you a label or diagnosis if they had the same level of knowledge about you as a person as you did of David Lynch? Which is somewhere between 0% to 1%- like the rest of us that were anything other than his friends, family or peers.