There are always going to be psychologically fragile people, homicidal maniacs, ignorant people, irresponsible idiots, abusive spouses, violent gangs, robbers, one time murderers, and people who make mistakes.
If you were in a room full of these people, would you rather have them carrying a few baggies a weed and some papers, or a loaded gun? Would you even rather there just be a shop in the room where all of the eligible people in the crowd could buy a gun and ammo?
10 yr olds are not legally allowed to purchase or own guns because we all know letting them do so will result in them killing people. There are a shit ton of people in america who should not have guns, and they can get them legally. You can point your finger at the person and say it was their fault and not the fault of the gun, but in the end, the fact that they were able to get a gun lead to someone getting shot or killed. The person that is dead doesn't care whose fault it was as much as they would rather have not died.
The fact that the gun is just a tool, which in the hands of the wrong person will lead to murders, does not mean that guns are safe, or that allowing the majority of the public to own them is safe.
So i am not saying guns should be illegal, just that we should be MUCH more strict about who is able to get any sort of gun.
And compared to marijuana? WTF is a homicidal maniac gonna do if he can just walk to the store and get a Kg of weed? Suffocate someone with it? Why not just go to the store and get a gun?