Very true xmirage2kx, but I don't think some of your examples fit very well.
Laws DO prevent crimes. No, they don't stop them altogether, but could you imagine if we had no laws? Would we be more safe? Absolutely not.
What we need is laws with punishments that fit the crimes. If there were no penalties for speeding, would we be better off? No. But we all take a calculated risk of getting in a serious accident or getting a ticket if we speed. This risk is increased in proportion to how much over the speed limit we drive. The punishments and risks balance out well with the crime. Some happily accept the risk of injury or a ticket while speeding, while others don't. Overall, it works out quite well for most all of us.
On the other hand, the problem with murder, drugs, robbery, and illegal immigrants is largely that the punishments do not adequately match the crime. Illegal immigration has virtually no punishment, so why not do it? Murder, drugs, and robbery would likely be less prevalent if we were better at catching violators and better at punishing them. Those that rob know they have a good chance of getting away with it and if they do get caught, the punishment will likely be small. If they ALWAYS got caught and ALWAYS got punished, no one would steal.
But none of these things you list can be related to gun ownership. While it's always wrong to murder, do drugs, or steal, there is absolutely nothing wrong with simply having a gun. There's nothing wrong with using a gun. The only time gun use should be punished is when it is used in connection with another crime, and when done so, the punishment should be greater than without a gun.
I'm not totally disagreeing with you, but I do think there are distinct differences. Just my $.02 (or by the looks of it, around $.25).