Even the media noticed that Obama didn't apologize when he backed off a bit from his original statement. Perhaps he came closer to apologizing when speaking on the phone to Sgt. Crowley--he just never can say "I'm sorry" in public for anything he has done or said (only for what the US has done or the previous administration did).
Just imagine if GWB had said anything remotely as egregious as Obama saying the police acted stupidly.
I have heard that the NY Post is running an article that claims that Gates is preparing for an upcoming special series on PBS on Blacks in prison and that this whole thing could have just been faked to advertise for his tv series.