Awful. Being autistic she may well have meant it at face value without it being an insult, and not understood what she did wrong as she just stated a fact. Then being dragged out while she had an autistic meltdown :(
Even if she did mean it as an insult and wasn’t autistic, there’d be still no need to drag her out and arrest her. She’s a kid. Educate her, sure, but there was no need to escalate it.