well that's an opinion, that he was trying to troll his school, the police, and America.
I'm going to go with the LCD of bored school administrators tried to humiliate a brown kid because they could.
Someone on another site pointed out that they never thought it was a bomb. Why? Well you usually don't parade a bomb around a school with its maker, or show the bomb to all the staff admin who want to see it. You probably don't have police displaying it outside of the school while arresting the kid, before driving off with the bomb and the kid together.
that is probably not how you treat a bomb. Or a possible bomb, or something that you think could make a loud noise.