No, it's not and it never was. Rioting is never really spontaneous. Behind every riot are riotmakers with an agenda. Sometimes their actions are deliberately planned and fomented, sometimes opportunistic, but always with a goal of destruction. Participating in every riot are rioters, usually folks who do not work and have been engrained with a mentality that the world owes them a living. The riot is an opportunity to take what they could not get honestly, and to destroy for the sheer unholy joy of destruction.
For both groups the riot is an end in itself AND a means to and end. Neither motivation has anything really to do with the supposed "spark" that we are told "ignited" the riot.