Racism through imagery
By discussing the appearance and features of stereotyped Mexican robots, the novel explains racism as a kind of perception error. They think the poor Mexicans are just robots, but they are accidentally showing their assumptions all the same. The various robots each highlight assumptions and fears that racist prejudices perpetuate.
Machinery and labor
By describing the Mexican laborers as literal robots, the imagery suggests that Mexicans are sometimes viewed as mechanical objects. The perception of Mexicans as machinery shows the heart of racial prejudice, because they are dehumanized and objectified. They are essentially slaves with no self or will (it seems at first).
The picture of progress
One might take the climactic scene for its imagery value. The scene where three newly humanized Mexicans are calling for revolution and revival is certainly a potent image, and it breaks the assumptive imagery of robotics and machinery. They are revealed to be organic and motivated. They want progress, so that people will consider them as valuable humans. It is a portrait of a socio-political desire for progress.
Money and economy
The novel describes plenty of economic interests. There is the farming economy of Sturdy Farm Worker, the underworld economyof Johnny Pachuco, and the middle class economy of Eric Garcia. The novel ends with them splitting the money that Mrs. Jiminez left behind, and throughout the book, shop owners are primarily motivated by money. The idea of disenfranchisement is suggested, because in all those instances, the robots are simply tools to earn other people money.
