I think it's more along the line of him not being able to stand the fact that they were going to get a chunk of the proceeds from the sale of the goods.
Per the Oprah episode. The Goldman’s (as owners of the book, ‘If I Did It’) will get the whooping sum of .17 per book sold. That is it. Simpson already rec’d an advance in the neighborhood of 600k (that the civil suit cannot touch due to FL laws). So that is why the Goldmans’ went after ownership of the book. They at least wanted to keep that .17 out of his hands.