To what other groups did Zinn compare the treatment of women? Why?

Groups that Zinn compare the treatment of women:

During the time period of 17th to 19th centuries in the United States, the condition of women was not nice and they were oppressed by the men of the society. According to Horward Zinn, women of that society were like the black slaves and were considered as invisible part of the society.

Women were compared to the black slaves because as the skin color and the facial characteristics of the Negroes make them different from the whites, similarly the difference in biological parts of the body between men and women made them inferior. So they were compared to the black slaves.