Is laughing at stereotypes in TV shows or comedians making racist jokes on stand-ups reinforcing racism?

Many comedians and television and film stars entertain their audiences by highlighting racist views in American culture. For example, comedians Dave Chapelle, Carlos Mencia and Margaret Cho and tv shows like, 30 Rock and South Park often use racist language and stereotypes in their acts. Racist comments presented in this way are not only accepted by audiences for their shock value, but are expected to evoke laughter. As racism is a negative, destructive force in America, is racist language ever acceptable in contemporary comedy and entertainment?