"Danish CS degrees are in high regard, and we’re all fairly good at English. There are a lot of Danes in Silicon Valley, I mean, C++, C# and Ruby were made by Danes, so it’s not like Murica isn’t open for us."

That is my point. Many of them move to the SV because they can get better conditions (caused by more leverage) there than if they stay in Denmark because there is a magnitude more tech companies there than in DK. I'm pretty sure they don't just move to avoid the rain :)