Are you saying that a robber had a sense of morality and they will not harm the occupants of the home? If so I have a dead cousin in Chicago who was murdered by a home invader. Said cousin didn't believe in having firearms.
In my experience, a couple combat tours, I have found people are less likely to attack someone with a weapons unless they are stupid or have a death wish. In any case, choosing to attack someone who is armed typically results in severe harm and/or death.
The premise of gun control has never been about safety. Just like with everything about the government it has to deal with control. Banning something or restricting access to something only makes it more difficult for those who care about the law and follow it harder to acquire said item.