Racism in our school

It's ridiculous how people have the nerves to still make fun of other people because of their religion or color. It's a free country and these students are not showing a good example. Even though we have had all these meetings about racism and respecting each other, it has not changed much. People still make racist comments. This guy in my class is one of the most racist kids i know. He is completely immature and I cannot stress it more. Who is he to say that Muslims celebrate 9/11? Or tell a Muslim he is a terrorist? What kind of right does he have?! I don't know what the school can ever do to change this. The only way is to do something about it once someone does something like that rather than wait for it to become worse. People should not just sit there and do nothing about it but to tell their guidance counselors or something of what is going on before it becomes worse. High School is the perfect place to experience all this nowadays but if students act, it can be prevented.