I am convinced that that is one of the reasons he was so THREATENING to the anti-abolitionists. The whole narrative of "Dem Black Men Gonna Come And Have Sex Wit' Our White Wimmins" thing was a deep fear, I think, and Fredrick Douglass was threatening since, well, you gotta figure that there were quite a few White Wimmins who might not have objected.

He was also, of course, smart, well-educated, well-spoken, a witty conversationalist, and passionate.