They are over the counter in Norway as well. And they are a culture of campers, hunters, and shooters. It isn't just a "couple nuts" with guns, it is pervasive in their culture and considered almost a requirement in some places to have a suppressor.

I have some family in Oslo, for the record. They often go into the gun shops and caress the suppressors, like a child you adopted out, love dearly, yet can never take back home with you. I get sent pictures from time to time.