In part I see it as an arms race kind of situation which is going to always be partly based on personal viewpoints; media presentation; costs and of course legalities.
In short if people grow up in an environment where "everyone owns a sword" and the media portray such a display as well; added to the fact that the costs of a sword are not too great and the fact that the government restrictions are not too harsh - then the population will in general arm itself to a level with the sword.
This is little more than our basic human mentality to have the same "power" or more "power" than others around us and a weapon like a sword is a quick way to convey power to a person quickly.
Guns are much the same thing - only they offer far more empowerment for far less cost to the person (you have to practice with a sword to be any good - shotguns you just point and fire

). So when you have a society like the USA it makes sense that a large proportion will arm themselves despite not having any major actual reason to do so.
Canada however has stricter gun laws (as far as I am aware) and the media and social aspects in Canada make less an issue of having to own a gun - so the culture of the population as a whole differs and thus you have a reduced number of guns in circulation.
Come to the UK and you've pretty much got even stricter gun laws and you're down to mostly farmers; the upper class; those wanting to be upper class and gun/rifle clubs. The social structure; the social pressure I should say, just isn't there outside of those groups to own a gun and the legal preventions for the average person make it a significant trial to obtain ownership - so you have to put more effort and thought into acquisition - not to mention costs and availability.
As for if guns make you more or less protected who's to say - if you can own a gun the criminal can generally own one too so you've not really increased your security; you just lined up with the opponent. I don't know if that means you should or should not own a gun - just that it means an "armed population" is not necessarily any safer than an unarmed one.