Just as a data point, all of these riots have taken place in commercial areas. They are not going through residential areas (even their own). It's hard to grab several boxes of Air Jordans, Hair Weaves, and bottles of Malt Liquor, going door-to-door in an apartment complex or even worse, going house-to-house.
The purpose of these "protests" is not to protest the event, but to rob and burn. It's simply Sutton's Law in effect.*
*-Remember what Willie Sutton said back in the 30's, when asked by a newspaper reporter why he robbed banks.
"Because that's where the money is."