Switzerland has stricter gun laws than the U.S. mostly centered around the purchasing of firearms as well as ammunition. Storage of weapons and ammunition is also regulated. Also, getting a license to openly carry a firearm is typically only given to those whose jobs require a firearm or for hunting or shooting competitions.

Also, Switzerland's population is about 0.025% of the U.S. population. The U.S. has 45 cities that are larger than Switzerland's largest city. The U.S. also has a higher poverty rate than Switzerland. Switzerland has a universal health care system as well. I would think that all of these are factors on why Switzerland has a much lower rate of gun violence than the U.S as well as the items mentioned in the post above.

"Swiss laws are designed to prevent anyone who's violent or incompetent from owning a gun.”

So between those two criteria, only about 5% of Americans would be able to own a gun and those 5% are the 5% who already neither own nor want to own a gun anyway.

"There should be only one questions on the application for a license to own a gun
Question 1 Do you want to own a gun.
If you answered yes to the above question you are hereby deemed to be an unsuitable person to own a gun."
Andi Parsons

Switzerland has a population of around 8 million and 2 million guns.
The USA has a population of around 340 million and 400 million guns
No comparison.
Also Switzerland did not have a Holywood promoted myth that when the European settlers were stealing the land from the indigenous people everyone had a gun and it was essential that they had.
I recall seeing a couple wearing T shirts with the slogan " The west wasn't won with a registered gun"