In what ways does "The Grapes of Wrath" promote hatred between classes of people, and even go beyond that?
Certainly, John Steinbeck meant to expose the plight of thos dispossessed by the Great Depression and the Dust Bowl. However, it does not seem that his aim was to antagonize; instead, he simply wishes for more to be aware of the tragic effects of the depression which saw many people become indigent overnight.
The reality is that hatred between these groups of people--wealthy absentee land-owners, displaced farmers, business owners eking out a living, business owners cashing in on others' misfortunes, bosses, migrant workers, strike-breakers, and more--already existed. This novel depicted the realities Steinbeck observed. His point of view was clear, and his condemnation of the powerful elite who were taking advantage of the common man was scathing.
The political and social unrest of the day could not have been helped by such incendiary images, it's true. Tempers no doubt flared, and the anger was probably palpable. However, I still come back to the idea that the conditions Steinbeck wrote about were real. If that's the case, it probably acted as much as an agent of hate as it did an agent of change. Read it, get angry, then do something to make it better, said Steinbeck.
When the novel was first published, it was openly criticized for being a "communist novel". Many people did not want to face the social injustices described in the book. The idea of strike-breaking, which occurs in the novel, was very unpopular. Large landowners and the manufacturing industry, both of which benefited from keeping wages oppressively low, scorned the book as a communist plot. The entire idea of Casy's "oversoul", the belief that all men are connected to each other and should work together, was thought of mirroring the communist idea of communal living. Since Communism is based on the idea of class warfare, the novel frightened many people who thought Steinbeck was advocating a change in the U.S. government.