Anyone who would act that way with a bunch of teenagers is.
Those kind of assholes are there for every march, but the kids just ignore them. Seriously, this is the most peaceful march in D.C. notwithstanding tons of teenagers and jerks like this guy being there. It is well coordinated and well chaperoned. It should not have gotten to the point where there was a stareoff with a guy banging a drum or kids doing the tomahawk chop. The adults with group should have moved the kids out of the way and told the guy to back off them.