After Squeak returns, she and Celie have something in common: they both have been raped by a relative. The white warden, of course, doesn't think that it was wrong to rape his niece — Squeak is black. In the American South, there is an unwritten law that if a person has any black blood at all in him or her, even the most miniscule amount, then that person is black — in other words, a non-person. This "law" came about, among other things, because of the greed of white slaveowners who wanted to have the most slaves. Accordingly, if a child had a white father and a black slave mother, the child was black and a slave.
Shug's impatient words to Squeak, when Squeak resists describing how she was raped, are significant: "If you can't tell us, who you gon tell, God?" The very first words of this novel, remember, were: "You better not never tell nobody but God"; Squeak then decides to tell her friends that she was raped. Celie, of course, decided to tell God; she had no friends to tell. Celie's rape is worse, ultimately, because as far as she knows, she was raped by her father, and he violated not only Celie, but he violated the sacredness and the unity of the family.
Squeak's suffering makes her stronger, and she demands that Harpo call her by her real name as Celie suggested earlier, in Letter 37. Squeak has earned the right to be called by her real name, Mary Agnes. In addition, she begins composing her own blues songs and stops singing Shug's songs. Tellingly, her songs are reflective; she questions, in particular, the double standard concerning color preference among black people.
Harpo's anger over Squeak's rape is impotent, as always. He talks about violence and revolution as a means of bringing about liberation and justice, saying, "I ought to go back out there with guns, maybe set fire to the place, burn the crackers [poor white Southerners] up." But Harpo only talks about his anger; he does not act on it. In contrast, the women act on their anger and frustration, and as we shall see later, they are successful in extricating Sofia from prison.