Your post makes a very good point that "not all" blacks will riot if Obama loses. I'm from that community, and know that to be more true than a lot of Americans do.
In the incidents you mentioned, only a small minority of the black community actually participated in that criminal behavior.
Unfortunately, if it's a close win by McCain/Palin, far too many opportunists in the black community will use that as their excuse to "take it to the streets."
My eyes will be cautiously watching the reaction of the black community in New Orleans given that I live in the greater area.