The internet exploded this week, and few could be happier than American Eagle, a fusty clothing brand whose denim had historically had all the sexiness of, well, denim. But these jeans contained the va-va-voom figure of Sydney Sweeney, a 27-year-old actress in the Hollywood hourglass form. “My jeans are blue,” the blond Sweeney told the camera in an ad that quickly went supernova. It was a pun on genes, but it struck several commenters as something more sinister. Progressives cried eugenics. Conservatives cried hypersexualization, though so did the left. In a country where few could agree, a surprising number of...