Canada (and I would assume England too, though I don’t know) has much stricter gun control regulations than the U.S. You have to pass certain tests and get certain references before you can legally own a gun in Canada.
I’ve also been reading a lot about the theory that the U.S.’s high rates of gun violence has to do with their cultural idea of what masculinity is supposed to be like (aggressive, assertive, anger is the only acceptable emotion, etc). Of course, those ideas exist in other places too, but I think they’re the most prevalent in the U.S. You can read more about this idea here and here.
Another thing is that U.S. culture is hugely fear-mongering. There’s an idea that the only way to be safe and protected is to have a gun at the ready, which is just ridiculous, especially when you consider recent arguments like that primary school teachers should have guns in their classrooms in order to protect the children from potential attacks. The skillset required to be a soldier or a police officer (in other words, someone who should have access to a gun and can use firearms to promote safety) is very, very different from the skillsets required for other professions, like teaching. It’s incredibly unreasonable and, frankly, stupid to expect that a gun will be able to make a meaningful contribution to safety in an environment like a school, in the hands of someone like a teacher.