[johngunderman]

A large part of this is that the Second Amendment to the US Constitution explicitly protects people's right to bear arms. This has led to gun-ownership being an important topic to many American citizens, initially by people using to utilize guns (ranch rifles, etc) and then by collectors and other hobbyists.

As for your second question, the difficultly of obtaining a gun in the US varies largely by state. However, it generally is not exceedingly difficult. As an example, here is how purchasing a firearm works in California:

http://en.wikipedia.org/wiki/Gun_laws_in_California#Firearm_...