nationalistic societies don’t keep to themselves. They each consider themselves “the one true society”, and generally try to expand as much as possible and make

nationalistic societies don’t keep to themselves. They each consider themselves “the one true society”, and generally try to expand as much as possible and make everyone else second class citizens. By “keep to themselves” i don’t mean communities should reject outsiders who want to join. They just need to not bother outsiders who don’t support them and don’t want to join. People from completely different cultures can and do exist together, however they share some other beliefs or commonalities; people who are polar opposites generally can’t coexist unless they’re separate. Even then, a community which rejects all outsiders and secludes itself would be fine. Like that one native tribe who attacks any modern intervention. As long as they’re not subjugating their own citizens and preventing people from leaving like North Korea.