Certainly, the boys could have moved, or ignored the abuse, rather than childishly outshouting their harassers. And at least one boy seems to make a tomahawk chop, which is horribly culturally insensitive.
But then, they are children. The charges against them are now downgraded to “not knowing the proper response when a Native American activist bangs a drum in your face.” And how many teenagers can be expected to have mastered that particular point of etiquette?
Adults, however, can be expected not to yell anti-gay slurs, or bang a drum in a stranger’s face. Which means that other adults can be expected not to single out the teenagers in this episode for failing to behave like grown-ups. And they can also be expected to apologize when they’ve wronged an apparently innocent child.