Entertainment or Cruelty?

My DGS is ASD and started mainstream school this year with a 1:1 SEN assistant. You only have to be in the room with my Grandson for 2 minutes and you realise that he is not Neuro-typical. He is a bright, happy little boy but probably about 18 months to 2 years behind in his emotional and social development. He is also dyspraxic so is very clumsy and doesn't always sense where his extremities begin and end. He trips over his own feet all the time!. He isn't naughty as a general rule but his need for sensory stimulation can mean he can be loud which obviously his key worker and the teacher have to try to quash. For the most part in school, he joins in enthusiastically but is finding some of the boundaries that the other children find easy, much more difficult. For example, the children are allowed to play pushing games (don't ask me why) and he doesn't always realise how hard he is pushing. The teacher says that he there is no malice or temper involved but wants him to temper his pushing. That seems to be a difficult ask but my son and his wife are working on it. Apart from allowing pushing games, they have no problem with the school, engage with the teacher on a daily basis to check everything is ok and are encouraged by the positivity of the teacher.
My son has had some concerns that certain children keep coming up to him in the playground and telling him that our DGS is "naughty". As they are 5 years olds, I tell my son not to worry, kids are very open, don't understand autism and are very friendly with our boy, he shouldn't be too concerned. My son is very keen that DGS should not use autism as an excuse for bad behaviour and wants him to be the best person he can be albeit with the neurological constraints he was born with.

However, at a Birthday Party of one of the children from the class last week, the "entertainer" asked who was the naughtiest child in the class. Every child pointed at our DGS and shouted his name. Our boy was oblivious (his language and understanding are very delayed) so was quite excited at everybody shouting his name but it was like an arrow to my son's heart. He is gutted that his son is seen in this light.

I asked my son what he had done and he said nothing. I said if I had been there I would have quietly spoken to the entertainer that this is not a question that should have been asked at all. Very many "naughty" children have issues which make them appear naughty and if they are labelled as such, it can be destructive to their self esteem and sets them aside from their peer group. My son didn't want to make a fuss but I think this sort of thing should be addressed even if it is only to educate. As a children's entertainer, there is surely a duty to be inclusive, show kindness and that picking on one child is not entertainment. AIBU?