He wasn't defrauding them, Rapparee, if he genuinely believed what he was telling them, and I think it's pretty obvious that he does believe in what he says. He's merely grossly mistaken, that's all. The end result may be the same as if he had defrauded them, but it's not fraud unless he deliberately meant to defraud people.

Like many other people with rigid beliefs (religious or otherwise), he was led astray by his own belief system and his own enthusiasm. The same can be said of his followers. They all put their faith on a shaky and questionable foundation, and they have all been disappointed accordingly. The same might be said of the many millions of people who once put their faith in Adolf Hitler. They made a serious error in judgement. Such errors are innocently made by millions of people every day in this world, but they usually don't get as much publicity as this prediction of Harold Camping's did. ;-)