They had to learn that abhorrent behavior somewhere, and obviously, due to the inaction of the chaperones (assuming there were some near?) and the defense by the punk's mother...it is condoned.
As for the school's public reaction, this smirky punk wasn't the only one in the group wearing political hats, so color me more than a little suspect...of the sincerity of the school's statement.
Not to even mention, that busing the kids to this event (by the school) in the first place...tells me a lot.