Muslims can't do that without becoming heretics.
Allah gets HIS message to His Messenger Muhammad,via an angel, and when Muhammad went to Medina, he had only converted about 150 people in the previous 13 years in Mecca.
Allah has Muhammad get the sword out in Medina to get more converts and that supercedes whatever he was doing in Mecca. - Tom
I know all that, so did the author of the book. He was a born & raised Muslim. Call it a heroic & obscure case for reform. Any way you have to read the book!