Sorry Alan - the introduction 'Is it Music preference or just snobbery if a performance is well sung and well played that it is not liked for other reasons?I will suggest a few examples and I expect you may come up with more.' I do not see as altering my view. Music preference or snobbery has nothing to do with nationality.
I might not like a scottish singer singing an English song because his accent sounds wrong to me. That is preference.
To not like him because he is a Scot is racist.

I do not want to get into a 'slanging match' here.
Just stating my opinion which I have as much right to express as yourself.
Just one example. (not folk I know)
Lonnie Donegan took a lot of American originated material, Tom Dooley, Lost John, John Henry, Big Grand Coulee Dam etc. & popularised a new style of music – skiffle.
Some I like, some I don't but I believe we would have missed out on a mass of enjoyment if he had been banned from singing them because he was British.

And I have not called you racist just pointed out that those 2 suggestions were ill-phrased!