Why did people go on the children's crusade?

A shepherd boy called Stephen said to the King of France that Jesus had told Stephen to gather all of the French children together and go on a crusade to free Jerusalem from the Muslims. Jesus had said that the sea would dry up to let the children pass. But when they got to the sea, it had not dried up. Eventually two sea captains, William the Pig and Hugh the Iron, offered to take the children across the sea. The children went aboard the 7 ships happily but 2 of the ships sank and everyone on board drowned. The 5 other ships went to North Africa instead of the Holy Land and the captain's real objectives were revealed - the children were sold as slaves and never made it home.