https://www.vox.com/policy-and-politics/2017/10/2/16399418/u...
1. The compare gun deaths. This includes suicides and excludes all other murders. So it is a totally biased metric.
They even admit most gun deaths are suicides.
2. Ignore by far the most salient variables for predicting murders.
Don't even get me started on the "suicide is always terrible" bullshit. Many suicides are rational responses to untenable situations. I'm glad that my grandfather had a gun, when AEC and his physicians had both failed him completely.
Looks like your numbers are badly off (those countries have less than half the guns the US does per capita, so not all that high), and in Switzerland there are a ton of restrictions on the guns (and on the ammunition!) compared to the US, to boot.
As to legal restrictions in Switzerland, that is absolutely true but orthogonal to the point I've made. The issue lies in the number of guns per person (and I'd personally argue the culture surrounding guns which spurs it), not the legal framework. South Africa has tighter gun laws than the US but still suffers from greater gun deaths (again, in total not mass shootings).