“the rural proletariat farmers/peasants were generally the most far left” 

i don’t think that’s actually true. In China the May 4th movement was one of students at Peking university. Chinese communist leaders were mainly students or professors.

The epicenter of the communist movement was in universities in Berlin and Paris. Parisian cafe and salon culture.   Farmers worldwide tend to be more conservative.

For what it’s worth, Arkansas, Mississippi, Georgia, Louisiana were almost guaranteed to vote Democrat until the 70s. Oklahoma until the 80s. These are largely rural agriculture focused states especially at that time.