In 1910 the foreign-born population was 14.7% and the drop around WWII was caused by other factors.

Much of the industrialisation and banking industry was driven by immigrants. Arguably the wealth of today is the product of managing to avoid the worst of WWII and profiting from Switzerland's "neutrality" but that's an entire conversation by itself.

Well they were neutral, its just most folks, even otherwise smart ones, don't like true neutral behavior if it doesn't actually favor their side, hence such 'smart' snarky remarks I can see all the time, by people feeling they know history. Swiss accepted everybody, hundreds of thousands of refugees too, some parts even when it became obvious they will all face starvation since they were completely encircled by axis. Private banks accepted everybody's money, just like every global bank did before and after the war.

They secretly helped allies - check Campione d'Italia story for example. Thats very far from neutral behavior. And so on. But most people don't want to know facts, they want simple black & white stories.

It continues till today - they are officially neutral but look at their moves ie against russia during Ukraine war. Completely aligned with west (well apart from US which has top brass collaborating with their sworn mortal enemy). Look how their army looks like - 100% compatibility with NATO, 0% with russia or anybody else. They picked their side, they just don't boast around it, actions speak more than 1000 words.