This argument is neither true nor false. Saying that only a good guy with a gun can stop a bad guy with a gun is not a grown up thing to say. First of all, who decides who is good and who is bad? If we look at the Wild West, where so many gun fantasies originate, the white pioneers had guns to protect themselves from the native Americans, while the native Americans had bows and arrows. Who were the good guys and who were the bad guys in that scenario? I think that this statement perfectly sums up the average American attitude to this debate, which is that Americans are not ready to have an adult discussion on the topic. They are not ready to put away their toys and talk like grown ups.