MacColl did not set up The Critics Group to remedy anything - he did so because a number of singers on the scene asked him to take classes.

I don't doubt your words, Jim - I'm merely taking my cue from the BBC blurb about the programme:

Immediately after the success of the BBC Radio Ballads, Ewan MacColl set about the Herculean task of trying to drag British folk music into mainstream culture. Frustrated by the dreary amateurishness of folk song performance, he decided to establish his own centre of excellence to professionalise the art. He called it "The Critics Group".

The second sentence of the blurb seems slightly at variance with your view - that's all.