You misunderstand puritanism, it has many tentacles that have stretched to many corners of american culture. It still has a strong presence in our standards of media "decency" where abominable violence is fine but naked bodies, eroticism, or rough language is clamped down on to an extreme degree. It also has lots of little weird echoes and side-effects. Consider, for example, the way that overly happy, "bubblegum" pop music is denigrated, especially by those who think that valuing "sophisticated" and "mature" music (whether it's classical, prog rock, speed metal, or what-have-you) is important. Or look at the legal prohibitions against drug use and sex work. Or look at the modern trend, especially online, of ironic detachment.

There's very much an undercurrent of looking at pure, unfiltered exuberance, enthusiasm, and enjoyment through a skeptical, dour, or peevish lens. The fact that people enjoy looking at porn in private doesn't change that.