That's a red herring.  Guns in the US are part of a problem with violence in America.  If you look across the globe, you won't see the American brand of fear.  In places like Africa and the Middle East, areas with guns are the areas with the most violence, rape and murders.  In Canada and most of Europe, the relationship is the inverse, fewer guns and less violence.
Because that's a gun industry talking point that has little basis in reality.  It's part of that "the only way to stop a bad man with a gun..." marketing ploy.
That's another gun industry talking point.
The reason that we need reasonable restrictions is not because of mass shootings.  I mentioned earlier that the number of mass shootings seems to constant (about 20 per year in the US), so that's a separate issue from the daily gun violence issue.
Gun control advocates make a mistake in bring up background checks after mass shooting events.  Background checks are needed to reduce the incidence of people who have criminal histories- particularly domestic violence- and mental health histories from obtaining weapons.  It's also an insult to our intelligence that one can be on a terrorist watch list or the no-fly list and still be able to buy a weapon.
Because of the push to expand the intent of the Second Amendment we have a big issue in that it is very difficult to remove guns from someone who is mentally ill and deemed dangerous to themselves and others.  And with several States allowing guns to be legally taken into places that serve alcohol, we've reached the point where rational thought has abandoned us.  
Ponder this: it's more difficult to vote in the US that it is to buy a gun.  To vote, you have to register well in advance of an election, wait until your registration is processed and then when you show up to vote, you have to present identification.   If you are a felon or you are deemed non compos mentis, you can lose your right to vote.  The restrictions on gun purchase and gun ownership are much more lax.
That doesn't surprise me.  Given the rate at which the gun industry is cranking out new product, the fact that a maintained gun can be used for over a century and the hoarding that has been going on in the past couple of decades.
It's an idea that came from the Virginia Constitution- take a look at Jefferson's original draft:
Proposing and drafting are separate things.
And take a look at the final version (
before the 1971 addition):
You'll also find a pretty clear statement in 
his 8th annual address (1808):