You say that like they're complete idiots. But this was in the 1970s. In Iraq. In a country that doesn't even speak English, or Spanish, with a completely different culture. They are also farmers. Most likely they saw the skull and thought it was about the killing of the fungus. Is it a dumb mistake? Sure. But don't pretend it's because stupidity is in their genetics. You can look at Iran's history, and find their contributions to science.