The house lights came up and it was intermission at “The Book of Mormon,” the new Broadway musical about a pair of innocent young Mormon missionaries sent to Uganda to spread the faith. John Dehlin, a graduate student who flew in from Utah to see the show with a group of Mormons from around the country, was still riveted to his theater seat, having flashbacks.

“It’s way, way too close to home,” he said, recalling his own missionary years in Guatemala: the shock at the poverty and violence, the pressure from the mission president to baptize more natives, the despair when his mission companion ran off with a local girl — and the Mormon mandate, above all, to repress doubt and remain relentlessly cheery.

A friend in the crowded theater aisle, Paul Jones, passed by and gave Mr. Dehlin a high-five and a hug. “It’s right on,” said Dr. Jones, a dentist from Gilbert, Ariz., “but I cringed a little bit, a couple of times.”

The arrival of a Broadway musical that ridicules their religion, produced by the creators of the scathingly satirical television show “South Park,” is proving to be a cringe-worthy moment for many Mormons.