Why is esperanza worried about the striker's efforts?

Because they don't want any thing bad to happen

Esperanza is worried about the striker's efforts because the strikers sometimes throw rocks at the workers, the strikers shout chants and threats, slip surprises under the vegetables like snakes and rats sometimes, and then the strikers are taken by the police and Esperanza is afraid that the strikers are planing to form a separate farm union, and she is afraid of the strikers coming back. The striker camp was also empty. She also at one point worried that she sounded like one of the strikers.