Hello hello! Been some interesting questions and comments going on here, and as I have been trained to be an advocate, I must answer these calls and teach more info!
JackHatchet asked if autism can learn social interaction with their interests - Of course! To a degree. I myself am proof of that (social science degrees all around!). And yet, the anxiety still can reign supreme on me some days and makes it hard to initiate contact (I've been rejected a lot in my younger days and never quite learned the core bits that are more or less impossible in this stage of brain development, stuff like that. I know better but the fear and anxiety hold me and I'm conscious of it as it happens). I am a social butterfly, once conversation and connections are started, but getting there is hard.
Ok, so to explain the issue of "mental illness" and "autism". See, the Psychiatrists (doctors), not to be confused with the psychologists (researchers) and counselors (direct helpers), decided to change how "autism" is listed. "Autism Spectrum Disorder" does not differentiate from difference autism type conditions - basically, asperger's syndrome doesn't exist in diagnosis except as reference, it's now "ASD". This made it easier to get insurance payouts for people with autistic conditions, or conditions of similar difficulties. So, "autism" means a VERY VERY broad field of problems now. A person who is mentally 4 years old for their whole life and a person who manages to build a warp engine are BOTH "autistic". Messed up right? That's the current diagnosis for a few years until we stop using the DSM 5 and move to a new model with autistic variants as their specific conditions.
Many with autism develop obsessions, it's specific and almost random. Mine was video game design but after my diagnosis I got lucky and got an obsession in autism itself. The falloff effect of that is this obsession includes knowing psychology, science, and all that stuff. Lucky for me.
The lucky ones with autism aren't as lucky either. Autism tends to lead to a slow mental growth. It doesn't stop, but it can be 10 years behind. I was probably 8 or so years behind by the time I finished high school and stayed a kid well until I hit 30, still am younger than my age even now. It can also cause intellect to increase. So, we now have an issue for the person. They may be 16 years old physically, hormones raging, mentally 8 and innocent as can be, but capable of doing graduate level education projects. Do we put them in special ed, and stunt their potential?, or in advance studies and watch them die socially without any support? It's a chaotic state of being and people with autism may have a suicide rate of 30 times the normal rate. Many of the non suicidal may die from lack of self care due to having miserable lonely lives that don't allow them to use their obsessions and potential or form meaningful relationships.
Honestly, the "problem" with autism is based on society. Proper understanding and programs would mean they could learn at a rate matching their chaotic identity and negate the lack of social growth to a hefty degree. Preventing rejection and promoting the obsession can lead to outrageously capable experts. Autism has always been around and it has benefits as well as deficits. It's most likely a natural occurrence to promote advancement and specialists within the human race.
If vaccines cause autism, then we need to find more vaccines to give to people.