Support for the 2nd Amendment is just that; the support of American's rights to keep and bear arms, as permitted by Constitutional law. Believing that they're an "important human right" goes beyond that legal precedence, and starts involving basic needs and rights (like food, water, shelter, etc) as well as often invoking (unnecessary) divine providence. The latter is taking things a step too far, in short.
If your question is for people of the latter, then I can't answer you that. However I support the 2nd Amendment for what it is, which doesn't elevate gun ownership above a privilege any more than driving a car is; all it does is "forbid" (for lack of a better word) denial of American citizens pursuing (through proper legal channels and regulations) ownership of firearms. Nothing about it states that you get a gun free of charge and check, it just states that we have a right to keep and bear arms.
Comparing us to other countries doesn't achieve much, as those countries still have issues of their own (some violence-related), and issues that don't parallel well to ours. London may have fewer school shootings, but how many bombings and honor killings do they have? Canada may not have "shooting sprees" (in where under five people die), but how many teens go missing in the woods at the hands of roaming psychopaths?
