What effect does the sarcastic tone have in the speech?

With dry wit and a touch of sarcasm, Truth occasionally expresses sympathy for men in the text. While onlookers or public opinion may have cast her, a black woman and former slave, as the appropriate target of pity, she takes the opportunity to turn the tables by instructing her audience to imagine the plight of men. This tongue in cheek approach makes her argument even more powerful.