This is a poem in which the poet is criticizing the double standard that men have for women. She is arguing that women can never satisfy men's expectations. This is because men seem to want them to be both the "Madonna" and "the whore." (I'm referring to the idea that men see women as either pure like the Virgin Mary or as whores.)
Throughout the poem, Sor Juana is trying to point out that men get angry at women if the women will not agree to have sex with them. But if the women do agree, then the men lose respect for them and say that they are impure. Sor Juana also argues that men have created an ideology in which their sins are ignored while those of women are exaggerated. For example, she asks who is more sinful -- the woman who sins for money (a prostitute) or the man who pays her.