Well, I don't know what he had in mind, or what constitutes a civilized society. The "deranged individual" in your example could have passed a background check, just like the sociopath in Aurora, Colorado did when he purchased firearms through legal channels. If legal channels were not available, illegal ones can be found. An individual who is set on destruction will find a way. I know that despite their best efforts, law enforcement cannot protect me from the sociopaths of the world. The police cannot be everywhere, searching every person, watching everyone. If they were, we would live in a Police State, not the United States. Therefore, responsibility for one's security and safety lies with the individual. Practice situational awareness, have an exit strategy, and be prepared to defend the lives of you and yours. Nobody else can, or will protect you. I have no illusions that an armed society will be without tragedy, accident, and some bloodshed. It is not a perfect world. I do believe that individuals have a right to defend themselves, and that none should infringe upon it.
More information about formatting options