I feel the reason behind Americans general pride in being able to own guns comes from the fact that they trough off a rather oppressive regime with there own weapons. Not to mention the fact that some of the most oppressive human rights violations have happened in places where the citizens owning firearms is illegal.
I feel everyone has the right to defend themselves, however most people really don't realize the skill needed to effectively use firearms. It is easier to learn and less perishable than skills with other martial weapons, and it is less dependent on the persons physical characteristics. It also takes some intelligence and common sense when selecting a firearm for personal defense. Take the S&W 500 previously mentioned, yes its an extremely powerful handgun. It however means it requires more practice to effectively wield it and it means you have a serious issue of over penetration. Whereas someone could more quickly learn to use a double barrel shotgun, and loaded with bird shot it would be equally or more effective with a much slimmer chance of punching though a wall and hitting an unintended victim on the other side.
As for Tasers and other less-lethal weapons, they can be effective at stopping violence, however they can still kill. So many people have died from Tasers that people are trying to get police to stop carrying them. There have even been deaths from Bean Bag rounds and the FN 303 which is basically a glorified paintball gun. So while effective you still have to be willing to accept the fact that using such an item can end in the death of the target. Is it less likely than with a firearm yes, but its still a possibility.
On the other subject of firearms from the US causing troubles in Mexico. From what I gather most Cartels use military level hardware, Full auto assault rifles, rocket launchers, and hand grenades. These are only legal in the US under very stringent Federal regulations. The likelihood of you finding these devices at a gun store, gun show, or even in a persons home is miniscule.
In short, yes firearms are designed to kill, but lacking them people still find ways to end each others lives. So blaming the tool itself is short sighted. I was a member of the military, I own firearms, if need be I would use them in self defense. However, I own them because I find the act of shooting at the range enjoyable, and I enjoy having fresh game on my kitchen table. So yes I support gun ownership, but I still feel sad whenever I hear about some jackwad using them to take an innocent persons life, just as I feel sad whenever I hear about someone crashing a vehicle into a crowd or going on a rampage with any other weapon.