I suppose the US is the unique one really, when it comes to a history of protecting certain types of speech. They've never really regulated (what I would call) politeness between people in any form.

The UK, and I assume much of Europe, criminalizes truly petty levels of speech. For example, it's illegal to insult someone and cause them 'alarm' or 'distress' in the street.

Thus the non-technical populace see rudeness on the internet as the result of some kind of wild west situation that the government needs to control, to bring it in line with the rest of the public realm.