We don't know yet, I imagine one day we'll find out his motivation.
I think he's being awkward, trolling people. The initial walk up and down was getting his courage up, working out what the reaction was going to be.
I think he's doing it to annoy the authorities, wind up whatever school grievance he has, and generally point the finger at woke culture.
I don't think it's a fetish.
It's still abusive to those children, and a disgusting parody of women.