I think that one line of logic that can be used with this particular prompt is the idea as to how lawlessness cannot be tolerated in a social setting. This would advocate that if individuals revert to breaking the law, no matter their motivations, society ends up crumbling fairly quickly. For example, regardless of what motivated the rioters, the city burned, property damage was huge, lives were ruined. The rule of law is what allows society to function properly, and once this is discarded, there is little guarantee of what can and will happen next. At the same time, I am not really sure the rioters' desires, whatever they might have been, overwhelms the damage caused to so many. The business owners whose economic viability became ruined by the London Riots did not shoot Mark Duggan. The children whose lives where endangered because of the fires caused did not shoot Mark Duggan. The people who saw their lives disrupted by the rioters did not shoot Mark Duggan. One reason why violence can never be tolerated as a form of public protest is because the people who are impacted are innocent. They had nothing to do with the source of the rioters' anger. They were "there" and because of this, their lives are ruined. For this reason alone, violence cannot be accepted as a form of social protest.