As reported, a Buffalo, NY woman was walking down the street when two men forced her into a car and searched her pockets for valuables. After taking $110 from her, they pushed her out the car and shot her once in the shoulder.
Criminals are unpredictable, and often mentally unstable. In this case that poor judgment and instability can be seen clearly. By shooting the woman, these robbers committed a much more serious crime, and made it likely that the police will spend more resources to catch them – all for no additional money or other benefit to themselves. It is simply not wise to trust one’s safety to the kindness of a criminal, who has, by definition, already demonstrated contempt for the law and civilized society.
Armed citizens, on the other hand, can act to defend themselves, rather than just hoping that the criminal decides not to become (more) violent. Sadly, many crime victims live in a state the either bans or heavily restricts concealed carry, leading to a situation where only the criminals have guns.