That's a folk music wave, a conscious soul album, conflated with more pop social commentary. Not much protest songs. Products made out of popular discontent.
Now if you said Woody Guthrie... But in pre-war times was there a non-mainstream?
The only thing that this may say is that in USA the regime fights dissent in mainstream media. Like, if you want to catch signs of a product made out of popular discontent, you can't e.g. find in UK charts the Sleaford Mods or Kneecap?
The last century was full of them. From Bob Dylan to Marvin Gaye to Crosby, Stills, Nash and Young to Sting to U2.
There were probably hundreds that made the Top 40 charts.