The United States is unusually ethnically diverse for a European colony but globally just about the middle of the pack. Most of the world is more ethnically and culturally diverse.

What the Swedish party in question is proposing, mass denaturalization and deportation of citizens (i.e. ethnic cleansing), is a human rights violation and violation of international law and wouldn't be done even by otherwise intolerant or autocratic nations. This harkens back to the darkest days of the Soviet Union and expulsions by Communist regimes towards the end of Yugoslavia, or early 20th century regimes.