Why would a historian find this to be a biased source of information? This passage comes from a white coffee planter named P. J. Laborie. He wrote this book to share his expertise with other Britons about the cultivation of coffee in Jamaica.

In order to make the best of the powers of the enslaved African, and to keep him helpless, punishment is unfortunately sometimes necessary. Such also is the case with soldiers, with sailors, and with all servile classes of men.

—P. J. Laborie:
The Coffee Planter of Saint Domingo, 1798