Mr. Taberski spends much of the podcast attempting to justify his invasions. Little details — like the fact that Mr. Simmons called in to “Today” instead of appearing on video — are used to rationalize the project. “Why wouldn’t he want to be seen?” Mr. Taberski asks, then conjures the image of “a kidnapper holding a gun to his head.” The implication: Mr. Taberski will rest only when Mr. Simmons is fully exposed.

Mr. Taberski told The New York Times that the podcast “was coming from a place of love and coming from a place of real concern.” In Episode 2, Mr. Taberski takes listeners on a drive up to Mr. Simmons’s gated home for what he half-seriously calls a “stakeout.” “I don’t want him to feel like I’m invading his privacy,” Mr. Taberski says. “On the other hand, I’m Richard’s friend.”

Is this what friends do? Turn their loved one’s personal crisis into a fun mystery investigation and record it for a hit podcast? (It has topped the iTunes podcast charts for four straight weeks.) Despite his claims, Mr. Taberski is not principally a “friend” to Mr. Simmons. In the podcast, he presents himself as a regular at Slimmons Studio who became friendly with the instructor, but really he was always a documentarian circling a sensational subject. (Talk of a film documentary dissolved when Mr. Simmons cut off contact with Mr. Taberski.)

The relationship between journalists and subjects shouldn’t be confused with friendship. Journalists have power over their subjects and a responsibility to try to minimize harm. But Mr. Taberski leverages his claim to friendship to reverse the equation, arguing instead that it’s Mr. Simmons who has the responsibility to speak to him, and to explain himself to his former acquaintances and fans. He compares Mr. Simmons’s relationship to them to the responsibilities of a licensed therapist. Mr. Taberski says he took care to ask Mr. Simmons’s manager “if there was something serious going on, like illness, so I could just let it be.” But is depression not an illness? Is a person’s gender identity not sufficiently serious to leave alone? Having decided that Mr. Simmons’s reasons for withdrawal are not “serious,” Mr. Taberski feels freer to pursue the guy.

“Missing Richard Simmons” speaks to both the possibilities and the limits of the emerging prestige podcast form. Many of the podcast’s tropes — the mystery framing, the crowdsourcing of clues from the audience and a format that focuses on the narrator as much as his subject — are borrowed directly from “Serial.” By turning a journalist into a friend and casting a man’s personal life as a mystery, “Missing Richard Simmons” has retooled the stale Hollywood documentary as an addictive media sensation. But it’s also turned it into a morally suspect exercise: An invasion of privacy masquerading as a love letter. Mr. Simmons is a public figure, and that gives journalists a lot of latitude to pry. But a friend who claims to want to help Mr. Simmons should probably just leave him alone.