Have you met Americans? We are addicted to comfort. You will certainly get cleaner using a bidet but a jet a cold water spraying your rear end seems like it would be quite uncomfortable. Caveat, like most Americans I have not tried it.
So far as I know, I've been an American for the ~50 decades I've been on this planet, and I'd say ~85% of the people I interact with on a day to day basis were born in America. I've observed that it is a common American trait to form strongly held views about things where one has no experience, and to defend those views fiercely. The Dude said it best.