Not solely an American issue: https://worldpopulationreview.com/country-rankings/mass-shootings-by-country

We're 11th in mass public shootings. It becomes a talking point when the state and media determine it to be useful tool for playing politics. If they actually cared, they'd tackle the root of the problem rather than pushing the same useless "solution" over and over.

You're right that this is a cultural issue. However, "gun culture" isn't the problem. The problem is the other aspects of our culture that leads to growing the state, political extremism, and dismantling community and families.