It's definitely culture and I believe that it's because of hundreds of years of the embedded
frontier myth which I don't think Europeans that haven't lived in the Americas fully understand the influence. For hundreds of years into the 20th century, most land west of the Northeast seaboard (and even that area at points) was the frontier where guns were seen as necessary tools to, at times, hunt and protect the family from wild animals and bandits and robbers. Lawmen and rule of law during the 18th and 19th centuries, for example, very often just meant punishment for a criminal after the fact not active protection for a community. This is why many western tales feature revenge not protection stories. Even with the 21st century being a completely different era, the effect of that frontier myth still endures. I don't think people can really understand American gun obsession without looking at the embedded generational influence of the frontier myth.
In some communities even now, the notion that the law and law enforcement won't protect you persists - which is why I hear from both black and immigrant people I know that are otherwise very liberal/progressive that they have guns because "the police aren't going to protect me and my family from the white nationalists, and in many cases, the police will be there protecting the white nationalists." They see publicized instances of police going out of their way to protect neo-nazis and white nationalists meanwhile treating BLM protestors drastically differently and they simply don't feel safe unless they protect themselves because the police are not going to protect them. It really is a vicious circle that will take generations of effort to change.