You can attribute the riots to naked human greed, selfishness, and lust for violence. And you wouldn't be wrong.
You can also state that the cause of World War One was naked human greed, selfishness, and lust for violence. You can say that they were the cause of the Holocaust. Of British colonialism. Of genocide in Rwanda. Of every terrible thing humans have ever done.
And you would be right.
But – and this is history 101 – obviously they're not the only cause. Because, if they were, riots and World War One and genocide wouldn't be events to be commented upon, analyzed, and condemned. They would be happening nonstop. Brutality is latent in all of us, but humans as a group don't go round acting on this brutality without some kind of cause. Even if the cause is only opportunity without fear of the consequences (in which case, we should be asking why there is opportunity and why there is no fear of the consequences).
By blaming only the greed and selfishness of individuals, who are you helping? What are you achieving? You're not helping people who have lost everything to the awful arson and looting. You're not helping the people who feel powerless, disenfranchised, and angry. You're not helping the people who feel so disconnected from society that they think it's okay to smash shops and steal stuff and set buildings on fire. You're not helping the society that has failed to make these people feel a part of it.
And you're sure as shit not stopping this from happening again.