What do the gas station attendants say that shows they don't know what it's like to be homeless, jobless, and hopeless? How does this promote prejudice?

The attendant claims that fifty cars per day go west, but wonders what the Joads expect to find when they reach their destination. He tells that one family traded their daughter's doll for some gas. Casy wonders what the nation is coming to, since people seem unable to make a decent living; he says that he once had used his energy to fight the devil, believing that the devil was the enemy. However, now he believes that there's something worse. The attendant shows just how blind and unfeeling he is to thousands of people living in distress.