Take an active stand against injustice by writing to your Congressmen and Senators about any problem in this country or in the world that you want resolved. For example, you can ask them why the top leadership of the Khmer Rouge are living freely when they should be held accountable for their crimes at an international tribunal. Ask your school board to require genocide education. Don't react to other people's anger. When you react, it makes the situation much worse.
Anger is a very powerful, negative emotion.
Emotion is not the equivalent to logic so no matter how hard you try to reason with people whose minds are filled with anger, they cannot listen to you. When the situation calms down, hopefully then you can work things out. Have tolerance for people of different races and backgrounds. There is no benefit to dislike people just because they are different than you. After all, we all share the same planet.