Bill Cosby served in the military, played sports, got a PhD (I didn't know that one until recently), and then became one of the best known and respected people in entertainment. "Cosby is now a leading educational philanthropist" indicating he gives back to the community. He also created a show about middle class African Americans doing well which is a pretty rare show to ever see on tv. How can he not be a great role model?
Also most of what he says has been said by others like Jesse Jackson, Cornel West, and Spike Lee.
So why the backlash? Probably because of the media's selective coverage of what he says - only showing the bad things. They make it seems as if he put all the blame on blacks when he didn't. They also took out the praise he gave to many black organizations and churches. Regarding Christians stopping drug dealers, it was in the context of saying that Black Muslims have done a good job of doing that on street corners and also that blacks have to do it because cops (society) aren't helping them in their neighborhoods. If anyone got bashed in that speech it was the cops.
You can find the text to all his speeches online without any media twists on them.
-Rudey