Insanity
Have you ever wondered if everyone else is crazy ? Maybe it's some type of "lead poisoning" thing again, similar to what is believed to have helped destroy Roman civilization? Apparently it does make a quite different, the type of metal you use in your plumbing . It has to be something like that. Otherwise, our only real explanation is that most of those nearly-hairless upright uptight barely-conscious hyper-active clothed monkeys are just completely whacked. That wouldn't bode well for the future of the species, would it?