Or it could mean that white people benefited from better education and privilege, there-fore having less reason to riot over perceived ills and taking alternative means of remedying the situation.
Or there could be different cultures at work.
My junior high was 1/3 white, 1/3 Hispanic, and 1/3 black. In 8th grade, a white kid was beaten severely enough to be sent to the hospital by a group of Hispanic kids. The vice principle (a huge black man with a commanding presence) got on the intercom and indicated that any retaliation would be dealt with severely. After school, all the blacks were in one large group, all of the Hispanics were in one large group in another area, and the whites were completely scattered---you couldn't find more than 4 white kids together in one group.
I found it interesting that the whites did not band together like the other races.