Early Intervention is what I did for 20+ years. I think autism to me seems treatable, and probably most of us working with kids are trying for helping them and their families with whatever challenges they may experience so they can have the best quality of life possible. What came to mind to me was one little girl who was maybe two, and came in the room with her head down and her hair hanging over her face and walked around the room facing the wall. After a few months she had changed so much, not just from participating in our program but with her parents helping her develop, and it was good to see her smiling and certainly she seemed much happier and was a different child from who I first saw.
That Wiki link Leo is one I haven't run across before and a quick search didn't come up with any reputable or medical sources I'm familiar with but I'm curious to do some more looking. (Temple Grandin would be someone to look up to get one person's experience on having autism.)
Anyway I didn't remember all the specifics of this situation since this has gotten to be a long one so I went back and reread it. It's good Rescue341 that you have an appointment to go in and talk to someone at the police station. It's unacceptable for someone to have thrown rocks at you so it would probably be good to follow up on what happened.
Seems like you'll need to figure out how to make going to the flea market a better experience for you. People who are vendors or regulars there can't read your mind - they have no way of knowing you're uncomfortable in social settings or why; they don't know why you keep walking around taking pictures but don't seem to talk to people or shop. If I was working a booth there and some guy did that I think it would make me uncomfortable and I would be wondering what he was up to if I didn't know the person.
You talked about how it is for you, walking around with headphones on etc. but you have apparently had some conversations with some of the people at the flea market. What about if you get a nice picture of one of their booths maybe offer them a look at it? or offer a small print. If you get to know even just a few of them maybe that will lead to some of the vendors becoming familiar with who you are so they might get to feeling more comfortable with you. I don't think people often get what photographers are doing anyway.
If there are some people there you've talked to already, that could be a starting point. Maybe you need to think about challenging yourself just to even say hi or nod to people occasionally. You don't have to have long conversations or talk to everybody.
And I'm going to give Tecboy the benefit of the doubt that he didn't seem to express what he meant very well. Having done events I think what he was talking about was that taking photos at events where there are a lot of people means a certain amount of interacting with people. Maybe not a lot, it depends, but if you can figure out how to enjoy it the best way for you and still find a way to try to help others understand you a little that might be worth thinking about.
As of now, Autism doesn't have any permanent treatment. Psychologists and counselors can only treat the symptoms, and recommend behavior modification; and this is temporary, at best.
Temporary doesn't necessarily mean a few days, weeks, or even months. But, eventually Autistics have a relapse, because the modifications don't change the root cause behavior in the patient. How severed the relapse is, depends on the amount of time lapsed if counseling has ceased, how much support the autistic gets (familial, social network, etc.), and what life style the autistic has.
Our son lived apart from us in a small town, with very little in the way of support. A different job took him even further away from our support. He eventually returned home to our area, sharing an apartment with his younger brother. The relapse was near total, and he nearly turned in completely on himself. It's taken almost ten years of counseling and treatment to get him to a point where he's making progress toward living on his own.
Autistics are also faced with external stimuli which compound the inward facing problem many Autistics face. This includes television, audio and visual stimuli, and overexposure to things like computers and games.
They also have problems with self-esteem, and confidence in their talents and abilities. And that's at the mild end of the spectrum. Asperger's compounds the difficulties.
Our last discussion with a psychologist revealed that there is no real "cure", just constant reinforcement of "good" behavior cues.