This excellent vignette that makes up one of the chapters of this coming-of-age novel concerns an epiphany regarding Esperanza's own sense of sexuality and the role of women in her community. Note that what produces the reaction you have highlighted in the final paragraph is the way that Sally has been pressurised into playing various "games" with the boys from the neighbourhood. At first, Esperanza is appalled and wants to protest violently at the way that Sally is being pressurised sexually:
I don't know why, but something inside me wanted to throw a stick. Something wanted to say no when I watched Sally going into the garden with Tito's buddied all grinning.
When she goes to Tito's mother, she does not find sympathy for her gut feeling. Likewise when she returns to Sally, she is made to feel "crazy" and "ashamed." The garden, which had been such an excellent place to play, and her feet, are both now tainted by the knowledge that Esperanza has gained about what happens between girls and boys in her community, and how wrong it is, but how nobody does anything to prevent it or protest against it.