How many Westerners can Sam Harris find who defend female genital excision? There basically aren’t any, and indeed the overwhelming majority of those who denounce female genital excision are secular Western leftists, precisely those whom Harris would presumably denounce as moral relativists. The defense of female genital excision is carried out by Muslim men and women who live in the countries where it is practiced. And here’s the key: Western governments have had no trouble whatsoever enacting or enforcing bans on FGM on their own territory, while Western anti-FGM activists have had only moderate and gradual success in fighting the practice through propaganda in the countries where it is practiced. And neither of those things would change one whit if we decided that we had some kind of science-based morality in addition to the Western rationalist secular moral tradition that has been getting along quite well over the past several hundred years.
I am a big believer in science. That’s why I think it shouldn’t attempt to generate knowledge in fields where it can’t generate knowledge.