maybe...don’t have time to really research it now so I’ll take yer word for it
i always remember that brawny exaggerated look from those WPA arts from school book binders and library murals from when I was a boy in the late 50s and 60s...i always think Steinbeck
from works done in that era which lauded the laboring man
there was even a bar-food joint in South Beach in the late 80s when I lived there decorated as such and called WPA
You’re right it was adopted by the WPA, too, but I think it started with the Soviets and even the Nazis. The proud, but potentially downtrodden, “Worker” motif was popular on many fronts during the era.
The WPA “worker’s art” of the 1930s was taken from the Soviet “Socialist Realism” school of “art.”
Liberal ‘rats in the 1930s idealized the USSR. Remember the NYT Pulitzer Prize given to the reporter who hid the Ukranian forced starvation that he eye-witnessed. He praised the USSR up and down. “I have seen the future, and it is working in the Soviet Union” etc.
It wasn’t until after WW2 that the liberal love for communism was beaten back and forced underground for a generation. But as we have seen with Ayers etc, it has always been latent like a fatal virus in our body politic.