It’s weird because Switzerland is one of the most armed countries in Europe, as in they have firearms but barely any shootings of any kind (so you don’t often hear news equivalent to a guy shooting students in a classroom or killing people at a shopping mall over there). Part of it has to do with the draft (most people who purchase firearms have a form of training, as they learnt how to properly handle them during military service).
I don’t know much about Switzerland, but America has an incredible dehumanizing education system where if you don’t fit into a highly competitive capitalist, you have no value. Some kids don’t feel like they want to be a part of that, but they don’t have an alternative, so they don’t care anymore. Adults that that happens to become deranged and may think shooting up a school is doing the kids a favor. A few of them have had copies of Catcher in the Rye in their pocket which has those themes.
It’s not access to guns that’s the problem. It’s that we fundamentally have a broken psyche at a social level.