He probably would have better manners, Tom. But his better manners would involve putting a polite gloss on the fact that her voice sounds to him like mating cats.
Was MP being impolite in referring to trad folk as "ghastly"? Probably, yes. Was he being truthful? Also yes, according to his ears.
The "accent" I refer to is not Irish, but the nasal tone used by trad folk singers. As you know, there's a reason for its existence - it lets a voice cut through a crowded, noisy room without amplification. It's as much an accent as a trained operatic voice is an accent.
Yes, I can appreciate technical ability in pitch, and I can appreciate technical ability in choice of songs and quality of research. And if someone's singing like that when I'm doing sound, professionalism means I'll do my best to make them sound good (although given that I might try to tame the nasal-ness, I might not be your ideal choice as soundman). It doesn't mean I like that style of singing any better.
And I've just done sound on Friday and Sunday nights for singer-songwriter acts. Not exclusively trad folk, but there were a few traditional songs in there. Hardly a one of them over the age of 25 either. Folk's alive and well and taking its chances with rock, blues, jazz, country and all the other genres.