When folks lack faith in themselves they begin to look for external scapegoats to blame for their perceived failings. They may attach themselves to, say, Catholicism and end up fighting Protestants in the Thirty Years War or later in Northern Ireland. Or they may become a Sunni Moslem fighting Shiite Moslems for no good reason.
Folks who feel good about themselves have no need for these sorts of external conflicts. Moreover, there is nothing special about religious values. People know instinctively what is right and what is wrong. Religious values are nothing more than the values that any good person would base their life upon.