I do like playing with guns, but surely the easier it is to get hold of guns, and the more guns there are in circulation, the more chance there is of gun related incedents. It's OK saying that it's a good idea to have them for self-defence if someone breaks into your house, but that just means that the burglar is more likely to carry a gun. Therefore the people who choose not to keep a gun are in more danger.
Also, what happens when someone who has a gun for self-defence has a breakdown? It is so much easier for him to go on a rampage and kill lots of people.