Steinbeck intuitively writes people as though they are more or less similar to each other when in a group and only shows them unique when alone. Striking then when a new character, the Jehovist lady, comes along and seems like such a bother.
In turn, the term Oakie lumps everyone into one similar lump and nobody is seen as a human being; animals.
It’s still a problem today with how migrant workers are treated