Why do some conspiracy theorists believe man never walked on the moon?

Conspiracy types will believe anything if you tell them first that it's special knowledge only available to a few and that the gubberment (or scientists, or the church, or someone) does not want them to know. Hint that there is an evil conspiracy from these sources against the believers and you have a market for whatever garbage you care to invent. Bermuda triangle? Chupacabras? Chem trails? Project Blue Beam? Alien abductions? Roswell? Claim the Moon landings were faked? Someone somewhere is making a little money from these frauds.