He was not even in the right area, under the tent, for his school. He was ask to leave when he did the stabbing.
Why did he even have a knife to begin with? Why was he under the wrong tent? That is why I wonder if he was up to something.
Blacks often purposefully engage in antisocial behavior and then dare someone to stop them, whether it's playing loud rap music or smoking on the subway, doing "prank" videos where they harass innocent people, or taking in spot in reserved seating that doesn't belong to them.
For them, it's recreation and a way to assert dominance.