As Dick and I come from the same era and influences, I am in agreement with him in terms of the labor based, socialist bent of the major figures in American collecting. The Lomaxes, the Seegers, Carl Sandburg, Kenny Goldstein were all leftist to one degree or another. The primary publication of the folk revival, Sing Out!, was an unashamedly advocate of "progressive" causes. The Weavers, who influenced millions of folksingers, were overtly politicaly aport.
I hope everyone knows that the Bosses Songbook was not a right wing creation. It was compiled (mostly, by Roy Berkeley and Dave Van Ronk) as a parady of the classic left wing People's Songbook. Van Ronk, of course, was about as far left as one can be and stay out of jail. There was a story that he had been kicked out of a Trotskyite splinter group for being too radical, but I don't believe it.
In those days, we had a sense of humor about our political passions. I remember a great anti-CP song called
The Ballad of Harry Pollet" that ended with the lines,

The moral of the story is easy for to tell,
If you want to be a Bolshevick, you ought to go to Hell.

                     Mike Miller