What if they were the victim in some way? Of course violence isn't justified, but isn't it entirely possible that the person was in fact oppressed by others and that is what drove them to be violent? I feel like people have a tendency to assume that whenever there is a conflict between the individual and the greater collective, that the individual's point of view is invalid. What is morally right always seems to be determined by the majority opinion. This is why society is all powerful and people who deviate from society's norms will usually end up defeated and shamed.