Barely halfway through “Joker: Folie à Deux,” the Joker’s star-crossed lover Lee Quinzel (Lady Gaga) asks her beau: “Isn’t this more fun than a movie?” Quinzel may be right to distinguish...

Released in theaters less than two weeks ago, the film “Joker” is already awash with controversy. “Joker” traces the evolution of Arthur Fleck, a mentally ill outcast who is relentlessly terrorized,...