If you see a person without legs, do you tell him he is a piece of shit because he can't run? So why harass autistic people?
The same is true of basically anyone that doesn't fit into what you typically see - there's always some people that will treat them poorly. It's unfortunate, but was probably adaptive during our evolution, and something we just have to deal with today.
If you have not yet realized it, here is a black pill for you: most people are deeply manipulative and bullying basically all the time. For example nearly all social rules that are commonly accepted in society are basically about which kinds of manipulations and bullying of other people are accepted by most people vs not.
With this in mind, the answer to your question
> So why harass autistic people?
is trivial: because it is currently socially mostly accepted.
They have to hide themselves because it's socially acceptable to harass them.
It's been proven multiple times that neurotypicals refuse to interact with autists automatically https://www.nature.com/articles/srep40700
Their experience of the world is a disorder "to be cured"
If the future is here but not evenly distributed then the dystopia is here but not everyone lives in it. Some maintain it.
What exactly are we doing here?
This is, in fact, not true.
Can you elaborate on that?