Are we "typical evangelicals" really all that different from a Harold Camping who refuses waking up to reality?

Absolutely. Many of those who are harping on Mr Camping today are doing it for the wrong reason. They are unhappy with him for trying to set a date for Armageddon. Few of them are questioning whether the background story makes any sense at all, or whether the Bible should even be worshiped as though it was suddenly zapped from the sky by God himself. They agree with this puerile waiting-for-Santa-Claus mythology. The only thing they're unhappy with is he tried to pinpoint it.