I got shouted at 'are you a boy or a girl' all the time as a child, as a girl with short hair, and I was fine with it. I understand it may be a more sensitive issue for a trans person, however - trans people, as I understand it, are a protected group, and women with short hair aren't and there are reasons for that.
At the same time, I do think the response was OTT
I haven't 'decided the guy was guilty' - I am saying the title of this thread an subsequent discussions seem to be presenting this as though 'innocent child with autism made an honest mistake' and the circumstances don't seem that way to me. Unless he totally randomly decided to shout 'Are you a boy or a girl?' at a random man and it was awfully bad luck that man happened to be a trans man who looked unambiguously male (which this guy does). Maybe IRL the guy is small and slight, but surely you'd shout out 'shortarse!' or something rather than querying their gender?
Seems to me:
Mistake - unlikely
Hate-filled invective - also probably unlikely
Intended as a bit of a joke without realising how upsetting it was - quite possibly
So all in, charge probably not very fair considering accused guy's social issues.