You can store European eggs for longer because they're unwashed, precisely because they're dirtier. It's a value judgement, and I don't think it should be regulated either way.
While I can't speak for all European eggs, you can store UK eggs for longer, outside the fridge, because they are likely to be significantly less dirty at the point of collection, the chickens they came from are less likely to be infected with salmonella, and because they are not subjected to a damaging process (washing) that aids the transfer of harmful substances from the outside of the egg to the inside.
I am under the impression that European eggs are not refrigerated. My understanding is that once you refrigerate an egg, the membrane separates from the shell, requiring that you continue to refrigerate it, as the egg is no longer properly sealed. Since American eggs are refrigerated to begin with, you need to continue refrigeration.