What is the best approach to curb racism: censorship or expose and punish?

If you have an alternative approach that you have seen used, then say so. In my life, I have observed these as the two primary strategies; either "shelter" the public or completely immerse them in racist propaganda in the news, while punishing those who act upon it. It seems that we now see all kinds of subversive racism on Y!A, in the news, in government; however, there is still an effort to censor and punish racism; where do we draw the line? Which one works better?