But I just can't...
I just cannot get past that what one does in one country is done in that country, and for another country to prosecute you for that is overstepping its jurisdiction.
-Renegade
OK here is an extreme, and deliberately silly, for instance a UK citizen writes extensively about the need for uprising, rebellion and civil war in the US. Their writing is particularly effective at increasing tensions in the US and riots break out. The author being very pleased with themselves visits the US to view their handiwork - they don't actually get involved with any of the action but would the US government not be interested in their presence.
It wasn't that long ago that a UK representative at the UN was denied entry to the US simply because he was muslim - they let his white wife and children through before he realised what was going on.
Don't forget the US go one further - they go into other countries and snatch people that they consider a threat to US security, imprison them indefinitely without due process or access to lawyers.
You can't really expect other countries to give US citizens special exemption from their laws - no one is denying freedom to write or discuss opinions of a Royal family in the US but if you visit that country afterwards that was also his choice. Even in the US freedom of speech often has consequences!