Alternatively, "you want to do business in our country, you must follow our rules".
Not that I agree.
However, for me there is a strong difference whether a monopoly chances rules (or as time goes by, the world changes - see move/music distributors) or people accepted it before it was a monopoly.
E.g. imagine that Germany say that HN needs to have pictures or, at very least, thumbnails. ;)
This is a weak slippery slope argument. Germany is not making arbitrary requests on web sites. Rather it is protecting the right of its citizens to anonymity, according to pre-existing laws.