This seems to happen at least once every fall. Yet another reason why ethnic groups should not be mascots. Full story is here.
Imagine a high school whose mascot was Jews, and opposing teams could say “Get Ready for a Holocaust!” Or maybe we could have the Mexicans and a banner that says “Get Ready for the Border Patrol”. (And there have been kids from predominantly white high schools displaying “Make America Great Again” when playing football against predominantly black high schools.)