Violent crimes are committed using "TADA !!!!" VIOLENCE, guns, knives, heavy blunt objects etc etc ....
Its generally the case that if a person is going to commit a violent crime that they think the can exercise some advantage by doing so, steal things, force someone to do something or just plain kill them.
The argument that you should NOT be able to defend yourself is flawed to this extent that arguments that say you are safer being unarmed don't take into account that many people get killed or seriously maimed as a consequence of violent crime. Would you be happy with the phenomenon here in Sydney where persons of west African appearance commit violent crimes in gangs carrying and using machetties ?
At least if the intended victim can shoot back they have some chance of avoiding the consequnces of violent crime. If the attacker ends up dead, who gives a PHUK anyway ?