Well, people who are intent on hectoring everyone else in the world into believing the same as they do about something often cause more harm than good, don't they?

This is true of religious prosyletizers. It's true of anti-religious prosyletizers. What would happen if you put Pol Pot and 1500 of his most faithful atheistic followers on an island with the Ayatollah Khameini and 1500 of his most faithful Shiite followers? ;-) A lively old time, I should think.