Yes, Ewan McColl et al used a technique that became the butt of tedious anti-folk jokes for decades- but the real issue is, why did the British feel the need to denigrate their cultural heritage in this way, while at the same time embracing American folk-roots culture, especially the blues. And today it's still generally considered cool to sing the blues but not to sing English traditional music, even in many "folk" clubs, where "anything goes" as long as it's not English.

I suspect a lot of it was simply because MacColl was a Communist and so anything he was closely associated with had to be ridiculed by the right-wing establishment, be it his singing technique, his musical material, the facts of his biography or the venues he worked in. You can't often mention his name in any thread in any discussion forum, even today, without some Tory nutter frothing at the mouth about one of those subthemes for dozens of followup postings.

You leftpondians had the same with Pete Seeger and the banjo.