I also think the issue is what people perceive to be racist or homophobic. A lot of the time the problem isn't with the original statement, it is to do with the perceived intention of that statement by the person being offended. For instance, in Scrubs, JD calls Turk 'Brown bear'. Is that racist? some will say yes, and some will say no, but if you watch the program there isn't even the slightest thought that it could be racist.
Difficult subject as how offensive a statement can be is judged with the eye of the beholder.