Re: It's not the guns, it's the culture.
"If you look at murder rates (roughly 25% of the gun deaths in the US are homicides, most of the rest are suicides), and the number of guns, and the severity and restrictiveness of gun laws, across all countries, it is not the presence or absence of guns or the strictness or laxity of the gun regulations, but the economic and cultural nature of the environment that dominates in determining murder rates."
That was such a convoluted sentence/paragraph that I fear I may have misunderstood your intent. What does the statistic in parenthesis have to do with the murder rates? They aren't directly correlated, cited, nor likely correct. The US CDC lists firearms deaths as such: The two major component causes of firearm injury deaths in 2014 were suicide (63.7%) and homicide (32.8%). (pg 12 https://www.cdc.gov/nchs/data/nvsr/nvsr65/nvsr65_04.pdf)
Your opinions on cultural sources for violence is probably something I'm in agreement with. I have always found it strange that you could not show a bare ass or sex on television but easily see extremely violent scenes regularly on network TV during early hours. Shooting a suspect or blowing up stuff is apparently OK but the natural functions of procreation which almost all adults engage in (somewhat) regularly is taboo.