Because nobody sane in Europe is proud of IIWW, in fact is one of the darkest moments of the last Century. Millions of people were butchered. Pretty obvious stuff.
So you had a very dark time, when the population was disarmed, and some very nasty people with guns came in to occupy and butcher people without guns. Then those nasty gun-totin' people were eventually kicked out when other good people with guns came to fight them off. And the lesson you guys learn is that it's best to disarm the population again? So that if any more nasty people with guns come, you'll once again be helpless? Why not take your lessons from Switzerland, which was practically the only country no one wanted to mess with, and just keep yourselves armed?
Wow, Rassah, I'm sorry but you are demonstrating a total lack of knowledge of what you are talking about. Your claim regarding Switzerland is laughable at best (but I feel is pitiful because I'm sure many US "pro-guns" would agree on such a complete nonsense), the III Reich army could have crushed a country like Switzerland in one second, they were "spared" because they were neutral.
Also Spain, Portugal and Sweden were "spared", just because like Switzerland
they where neutral countries and not of strategic interest (at least in that stage) for the Axis. In fact, the strategic interest of neutral countries is crucial. You usually do not "mess" with a neutral country in a world war scenario simply because "neutral" does not mean only "I will not attack you", means also "I will export goods to your country, you can commerce here, spy, and I can serve as a safe place for refugees of all the parts". In the case of Switzerland, it also meant "everybody can sell me their gold if they need liquidity", which is a very useful asset in a world war scenario.
Last but not least, the German army didn't showed much fear when they violated Swiss airspace
hundreds of times despite of the continuous diplomatic complaints and the immense pressure of the Allies for this to stop (there were threats of Switzerland to be considered an Axis territory if Nazi planes continued to cross their airspace). I could go on forever but I would digress, I just tried to quickly show you how completely wrong is your vision about why Switzerland has not been involved in IIWW (and BTW, they weren't neither in IWW)...
Maybe you should do a nice trip to Switzerland, stay one month, and try to understand what is the relationship of its population with their guns, maybe you would be surprised.