Because of the silence between them
Even though Esquivel knows the story of maiz is a myth, she nevertheless warns her daughter not to step on a kernel of corn because the corn represents fertility and the kernels are part of the ritual. It would be wrong, or perhaps even sinful to step on such an important symbol of their culture which is why Esquivel doesn't want her daughter to be in some kind of danger because of such a reckless act.
Hmm...an easier way to find a theme of the story would be either scheming through the story looking for clues or facts or read it.
I hope this answer helps.
Animalism offers the animals a utopian existence. A life free from slavery, exploitation and abuse. Essentially, it offers them a life liberate from the tyranny of man. The concept is based on the principles of freedom, equality and brotherhood. Each animal will have the same rights and privileges as any other animal. All animals will be equal and no one animal will be superior to another.