People have completely confused the technique of disinterestedness in the service of scientific inquiry with the legitimacy—and necessity—of moral judgment.

When a person puts on his or her "scientist's hat," the thing to do is to set aside moral judgment in order to get a clearer and more complete look at the culture one is investigating. That's because bias is blindness. Preconceived notions cause people to jump to conclusions and miss important details of the culture (or history) they're studying.

The mistake is that far too many people fail to realize that at some point you take the hat off. You stop being a scientist and start being a civilized human being. Radical cultural relativism is monstrous.