It's all good, and I did even admit that the US isn't close to the safest country, just that the comparison to Brazil was inaccurate. As to why, there are likely many factors, including laws and culture, but, like I mentioned before, it may have something to do with the philosophy of the founding fathers and the emphasis on maximizing freedom that has been a theme throughout US history, as evidenced by Thomas Jefferson saying "I would rather be exposed to the inconveniencies attending too much liberty than those attending too small a degree of it."
Edit: Also, like I mentioned, guns are so omnipresent in the US that it may not even be possible to get rid of them all. Many states/cities with very restrictive gun laws still have plenty of gun-related crimes and murder. Asking people to turn in their guns doesn't always work for criminals. It's more nuanced than just saying that all the problems will disappear if guns were outlawed tomorrow. I mean, no one does drugs because they're illegal, right?