Author John Grisham has criticised the US justice system for handing down "harsh" prison sentences to those viewing indecent images of children.
The American said some of those jailed had probably had too much to drink and should have faced lesser punishments.
But the 59-year-old writer told UK newspaper The Daily Telegraph that he had no sympathy for "real paedophiles".
His comments have attracted criticism from child abuse charities and some legal experts.
Mr Grisham, who has sold more than 275 million books during a 25-year career, used the interview to launch a wide-ranging attack on America's judicial system for sending "too many people" to prison.
He focused his anger on the length of imprisonment imposed on offenders who download images of children being sexually abused.
He said a "good buddy" of his had been imprisoned for three years for viewing images of children on a website labelled "sixteen-year-old wannabe hookers" when his drinking was out of control.
"We have prisons now filled with guys my age. Sixty-year-old white men in prison who've never harmed anybody, would never touch a child," he told the Telegraph.
"But they got online one night and started surfing around, probably had too much to drink or whatever, and pushed the wrong buttons, went too far and got into child porn."
US judges had "gone crazy" during the last 30 years, he added.
"I have no sympathy for real paedophiles. God, please lock those people up. But so many of these guys do not deserve harsh prison sentences, and that's what they're getting."
But campaigners criticised the writer for apparently offering an excuse for child abuse.
"Mr Grisham's comments send a dangerous message that 'just looking' at images online causes no harm," Jon Brown from the children's charity NSPCC told BBC News online.
"In fact, every image is a real child who has suffered and every time these images are clicked on or downloaded it creates demand that ultimately fuels more child abuse."
Bharti Patel, chief executive of Ecpat UK, a network of organisations working to end sexual exploitation of children, said Mr Grisham's statement was "irresponsible".
She said it gave out the "wrong signal about the criminality of the acts of accessing and viewing abusive images of children."
Meanwhile, London-based child abuse lawyer Dino Nocivelli urged the author to meet survivors of abuse "to educate himself and to truly understand the inappropriateness of his comments".
The US has the world's largest prison population, with about 2.2 million adults behind bars.
In 2012, close to 25% of the world's prisoners were held in American prisons despite the US accounting for just 5% of the world's population.