What motivates Esperanza to help Marta?

Marta is a teenage girl who lives in an adjacent camp with her mother, Ava. Marta fights for the rights of migrant workers and organizes a strike. She often mocks Esperanza for her privileged upbringing and lack of experience doing manual labor. When immigration officials break up the strike, however, Esperanza helps Marta hide. I think that Esperanza sees Marta's vulnerabilities despite how she acts.