Sandy, there are many styles and you are certainly correct. Much of the criteria has to do with the folk culture from where these great fiddlers come. Cape Breton is certainly home of the violin, they don't call it a fiddle, Acadia is another, Appalachia, Bluegrass and so many different styles. I confess a bias here since I knew Jonny and worked with him in the early days and was blown away by his ability.

Jonny was a great dance fiddler and was known through Quebec and Montreal.

I'm not sure that fiddlers from various traditions consider those from outside theirs as being in bad taste.   For the most part, the great fiddlers I've encountered respect the ability of fiddlers from other traditions. The most difficult thing for fiddlers is to keep time for the dancers. The dancers are the ones who might not respect different fiddling traditions since they rely on those for which they are comfortable.