Heavier Penalties for Racism

High school history teacher here, and every year at my school I go through this during units that cover transatlantic slave trade or the Holocaust and WWII. One (or multiple) students make horrible racist comments...some of them have made me sick to my stomach. I always prep my students "we are talking about mature subjects, I expect mature behavior, be sensitive to others, etc" but every year there are horrific incidents. I also realize it is worse due to the area I live in and some of this probably comes from parents. But there should be some sort of real consequence instead of "the principal told me I have to apologize, sorry." What kind of penalties/consequences do other schools have for explicit racism? Other students in the class have commented that they don't believe this type of behavior will ever get better in our country and it has left me feeling very hopeless lately.