Probably a combination of cultural and legal factors. Basically, the U.S. culture is more violent in general and the U.S. government criminalizes a broader range of activity, which increases violence (gun-related and otherwise) for obvious reasons. The solution is just to give people more freedom. Fewer laws, less crime, less violence.
Here's a question for Atlas hoplophobes, if guns are the cause of relatively high U.S. violent crime rates, why is there no correlation whatsoever between the two:
Furthermore, when other Western industrialized nations tightened their gun control policies, crime in those nations
went up, which suggests that the reason those nations have lower gun crime rates than the United States has nothing to do with gun control, and than gun control itself is completely ineffective at reducing crime.
But, none of these facts really matter to the people who truly drive the power-agendas of the world. They want everyone to rely on the State for protection so that they can be easily controlled and won't object to crap like police militarization and various police-state measures. It starts in kindergarten when they indoctrinate kids into the pussy mentality of "don't fight back, tell a teacher." They want you to be absolutely reliant on authority and unable to defend yourself or anyone else.