Joker: Folie à Deux is a messy, overstuffed sequel that squanders its potential. While the cinematography shines, the film itself is a tonal jumble. It's a comic book movie devoid of action, a musical without memorable tunes, a romance lacking heart, a thriller without tension, and a character study that goes nowhere. The first film's focus on victimization felt like justification for violence, and this sequel doubles down, adding a toxic "incel" romance with a Harley Quinn who fetishizes Joker's…