No the system and other systemic or social problems are just a excuse.
Riots, at least those in recent events are an example of contagious social behavior. That is evidenced by the fact that the blamed issues have been known problems for longer than two weeks with people actively working for years to raise awareness of them. If other people are so passionate about these social problems that they are drawn to riot then where was this passion more than two weeks ago? Why suddenly congregate into emotional hysteria, especially since other people have been actively addressing these concerns for years, when the problems of complaint are preexisting and were clearly previously known to these congregants?