A mildly insulting comment hardly rises to the level of attempted murder. Consider fight outside a bar, if you want a real world analogy: if nobody is seriously hurt, and no property damage, police can tell people to break it up and go home, without arresting anyone. Same for letting a speeder or someone with a broken taillight off with a warning.
In any case, I fail to see how discussing this further would be productive, even if it wasn't off topic.
3 insulting comments. You are clearly not able to judge mildness or gravity of anything, standing on your denial of evidence, ostile and biased attitude. I am considering hurted by his comment and you are not respecting my sensibility and you are not making your job here. You should be ashamed of yourself for what you are doing here.
Like has been said, hate speech against autism is not covered by canadian constitution (nor by italian laws, actually), so your are refusing to take actions against a flow of comments that is actually against of your country's laws.
You are giving a so disgraceful image to your company too.
By the way, do you think is off topic and that it is better that I open a separate thread to discuss your behaviour?