WITH a sensational story of surviving child sex slavery in Cambodia, Somaly Mam became a worldwide icon, the best-selling author of a memoir and the head of a foundation raising millions in the name of saving girls and women from the sex trade, victims she recounted rescuing in dramatic brothel raids. Last year, introducing the State Department’s annual “Trafficking in Persons” report, Secretary of State John Kerry called Ms. Mam “a hero every single day.”

But all this wasn’t true. A Newsweek cover story last week found inconsistencies and flat-out fraud in Ms. Mam’s story of being abducted and forced to work in a brothel as a child — instead, former neighbors said she came to their village with her parents and graduated from high school, later sitting for a teacher’s exam — and in the stories of women she said she had rescued by the thousands. Ms. Mam even said traffickers had kidnapped her teenage daughter — but the girl’s father said she ran away with her boyfriend.

On Wednesday, Somaly Mam resigned from her own foundation.

The consequences of her fables will prove harder to correct. Ms. Mam and her foundation banked on Western feel-good demands for intervention, culminating in abusive crackdowns on the people she claimed to save.

The International Labor Organization estimates that more than three times as many people are trafficked into work like domestic, garment and agricultural labor than those trafficked for sex. I’ve interviewed human-rights advocates in Phnom Penh since 2007, and they raised concerns about Ms. Mam’s distortion of this reality. Her portrayal of all sex workers as victims in need of saving encouraged raids and rescue operations that only hurt the sex workers themselves.