Any topics as personal as religion or politics are best never discussed with total strangers. Should not historical intolerance or hostility toward people who have different beliefs/attitudes have been adequate reasons for the overzealous guy to wait until he was in his street clothes and look for converts? And only in person? No matter how well he was received during his stay in Costa Rica or wherever..........most people might not want to be 'converted' to anything, unless it brings them better security, food and shelter...
Is he fairly new to the "Blue Planet", with no historical awareness of the murderous human race?