Goldman and his daughter, Kim, appeared on "The Oprah Winfrey Show" Thursday to discuss the book.
The rights to the hypothetical memoir, which was released Thursday, passed from Simpson to Ron Goldman's family, following a bankruptcy judge's ruling.
The family stands to earn 90 percent of the profits from sales of the book, which is one of the top pre-orders at Amazon and Barnes & Noble.
On "Oprah," the Goldmans said the publication of the book was the only legitimate means for them to collect the $30 million owed them from the wrongful-death judgment against Simpson, E! Online said Thursday.
"We view it as a confession," Fred Goldman said. "This isn't an innocent man writing a book like this. An innocent man doesn't write a book of how hypothetically he would decapitate the mother of his children."
Winfrey said she will not read the book.
"I don't want to be in the position to promote this book because I, too, think it's despicable," she said. "I'm all for it being published, but I personally wouldn't want to be in a position to encourage people to buy this book."