Please explain the following passage to me: The whisper that my master was my father, may or may not be true; and, true or false, it is of but little consequence to my purpose whilst the fact remains, in all its glaring odiousness, that slaveholders have

Douglass is referring to the fact that his father was white, but the fact that his father was a white man had no effect on his purpose. Douglass saw the fathering of "slave" children who inherited their mother's condition to be a two-fold arrangement, as the "master" was able to not only satisfy his own lustful desires but profit from another addition to his wealth.