probably also people projecting the 2024 ideologically coherent party system into the 1930s. So it makes sense that at the time people understood and had labels for different factions of the two parties, but this whole mode of analysis is (for good reasons) just not done as much today.
That is literally the entire premise of Jim Crow.
Complete with the powers that be landing on any attempt to organize by class across race with a proverbial ton of bricks then burning the evidence.