what is douglass's purpose in the speech "the hypocrisy of american slavery, july 4, 1852"? how does douglass reveal his purpose to the reader?

Douglass's purpose in the speech "The Hypocrisy of American Slavery" (Given July 4, 1852) is to shame the American people specifically the people of Rochester, NY who have asked him - a former slave - to give a speech on a day of celebration of American freedom.

Douglass reveals his purpose to the reader through literary and persuasive techniques such as: rhetorical questions, ethos (ethics), pathos (pity), logos (logic), and anecdotes (stories).

"Fellow citizens, pardon me, and allow me to ask, why am I called upon to speak here today? What have I or those I represent to do with your national independence?" (Douglass, Paragraph 1)

"Fellow citizens, above your national, tumultuous joy, I hear the mournful wail of millions, whose chains, heavy and grievous yesterday, are today rendered more intolerable by the jubilant shouts that reach them." (Douglass, Paragraph 4)