I think many of us are not as taken aback by "classically trained" singers as one might think. I found three YouTube recordings by Máire Ní Scolaí here:

https://www.youtube.com/watch?v=TPM5KCMLCzU&list=PLaJu9PHxsRg97spytAZ4WsvHYp_K2Fr0u

I like them just fine, although I might like some of the "folkier" singers better. But the performances of Máire Ní Scolaí remind me of Paul Robeson, and that ain't bad.

On the other hand, there are some overdone, classical-style performances of folk songs that drive me batty. Some Mudcatters I love dearly, have personal or family relationships with singers I hate for their classical style, so maybe I shouldn't name names.

-Joe-