Funny or Racist

I have been thinking a lot about the line between racism and satire. In class we talked and defined satire as a joke that uncovered the injustice or misconceptions while a racist joke doesn't do anything to to combat the situation. So when does racism become satire and when does satire become racism? I think there is a lot of media and a lot of comics out there doing a lot of work on exposing racism through comedy. However I think a lot of the inherent racism in our society still gets by in media when it's covered as a joke. There was an Saturday Night Light sketch recently were two students were really obsessed with Japanese culture. They grossly misunderstood Japanese culture and were playing off sterotypes. There was a teacher to dispel the misconceptions, but I didn't feel like the scene put enough importance on him. In my opinion the scene was certainly intended as satire, but to a lot of viewers it probably just reinforced sterotypes. It's not really a good option to stop talking about racism, because no conversation is worse, but when do we know when the comedy is helping or hurting us?