Frederick douglass is very detailed in his description of mr. plummer. why?

Frederick Douglass is very detailed in his description of Mr. Plummer because Mr. Plummer and I quote “Was a miserable drunkard, a profane swearer, and a savage monster.” Mr. Plummer was the one that gave him the very memory of his aunt having her hands held by a hook and standing on her toes on a stool, and being whipped even after blood was pouring from her veins. He was a cruel man that didn’t care about what happened to the slaves. He was so descriptive about Mr. Plummer because Mr. Plummer left a “scar” on him. He left an emotional scar that Frederick will never forget.