I have a couple of cents worth to drop in. First I think calling Michael Moore Anit-american is a little simplified. I think he'd oppose anything that he could with his superior attitude to further his career. So I'd get plenty of balance before I took very much of what Mr Moore says very seriously.
Second, one thing to realize is that gun laws in the US vary greatly from state to state as to what they let people own, what their registration/permit practices are and their laws about concealment are.
I think the argument in america (trying not to be biased to one side or the other) is a struggle between whether gun ownership/possession by the populace is a cause of gun violence, or if the presence of guns serves as a deterent to crime and by extension do license laws and waiting periods have any effect (do legally purchased guns play much of a role in crime, or since criminals don't by definition follow laws are they non-factors?) Throw in arguments about the 2nd ammendment to the UC constituion and how to interpret it (right to bear arms, and the argument whether tha is for the restricted prupose of raising a militia, and thus possible archaic or whether the notion is that widespread gun ownership serves as a check against tyranny.
Don't know if that helped any, but that's how I see the arguments going here.