A kid with autism will often perseverate, repeating the same phrase or action, sometimes something appropriate, sometimes nonsensical to others, either because it is a form of self-soothing, because it helps them process, or because they feel uncontrollably compelled to. Or other reasons we don’t know. A kid with autism may not understand instructions, or it may take them longer to process instructions. That’s what it looks like to me.
I completely understand why you might say he was just a kid talking shit, as it resembles that and a kid talking shit in absolutely in no way deserves the actions the Vice Principal took. Notions of disrespect and talking shit are social constructs that us typicals pick up very quickly, but not every kid/person with autism can or does.
