Seems it's our fault initially along with the Native Indian tribes.
The rest could be down to technological advance.
https://www.washingtonpost.com/news/volokh-conspiracy/wp/2017/11/21/the-american-indian-foundation-of-american-gun-culture/
There's a lad I mentioned I worked with on here,the reason we had to join the Common Market was because they had dirt on our Royal Family partaking in a huge peadophile ring.