I am not at home and not in a position to read the thread, just Slag's thought-provoking intro. So apologies if I am repeating a point already made.

Slag was curious to know why aetheists don't just leave believers to get on with it. The answer in my case is that religious faith distorts loyalties. Or to put it more neutrally, it results in loyalties to perceived higher authorities which may, or may not, exist. The self-distructing jihadist is an extreme example; a slightly milder example would be the 19th century mill worker persuaded to expect his reward in heaven rather than hope for it on earth. Moreover religion has been exploited by many regimes, not least Constantine's, thanks to which Christianity not only survived but became one of the world's leading religions.