Well, I think we should make a distinction. Hoax believers usually have little sense of humour. Those who actually create hoaxes often have too much.
So, when believers ask in outrage, "Why would anyone fake a UFO sighting?" the answer is often, "for the lulz". There was no profit motive, nothing deep and dark. Just they thought it would be funny to put candles in bags, and see what people made of them.