I mean, a rainbow Gadsden flag makes some kind of sense if you forget all the recent associations. At face value it could be as simple as saying that you don’t want the government to tread on your rights as an LGBTQ citizen. If you go one layer deeper and look at it as a symbol of the fight for freedom during the American revolution, it still works - Freedom for LGBTQ people to be who they are.
Having lived and worked in several countries, I think the concept of Jantelagen is rooted in the Protestant Reformation more than it being a specifically Nordic thing. Not only does it fit well with the general premise of the Protestant worldview, all countries that were early converts seem to have ingrained that particular perspective (under various names) in their collective cultures.