The dehumanizing irony
In the end, we learn that the robots were secretly human the whole time. They had been ironically dehumanized in the perceptions of the buyers and sellers, but in real life, they were human and that was concealed through dramatic irony. The irony of dehumanization is also implied. Dehumanization is ironic because human nature is not something that can or should be removed from a person.
The ironic 'honesty' of Sancho
Honest Sancho is ironically kind of a snake. His wily business practices keep him constantly busy, pushing people to buy his robot Mexicans. His irony is doubled by the fact that as a Mexican, he is buying and reselling Mexicans. He is a hypocrite and a traitor because he reduces people to objects and sells them as literal robots.
Mrs. Jiminez's ironic role
In the story, the character called Mrs. Jiminez has an intriguing role. It is ironic because although she comes to pay a vendor for a robot slave, she ends up panicking when she realizes the true power and sovereignty of the "robots," that were secretly just normal Mexicans the whole time. Ironically, she leaves them a bunch of money, basically on accident, so they benefit from her wrongful intentions to use them.
The irony of revolution
There isn't a revolution when the robots-revealed-to-be-humans start chanting "Viva la revolucion." This means that their ironic intention is to respond to the novel's stereotypical and offensive ideas. The revolution is perfectly ordinary, but it signifies something deeply important. The ironic chant shows that these Mexicans feel disenfranchised by their mistreatment.
The irony of racism
There really aren't any white people in this story. There are only Mexican Americans who are buying and selling Mexican "robots," but secretly, they aren't robots at all. They're just slaves, and they revolt wonderfully. But the irony is still potent—why should Mexicans be so mistreated by other Mexicans? Because Mexican American culture is also prey to racist ideas about Mexicans. That's a powerful irony.
