"The point is that there is a widely held belief that the English isn't a particularly good instrument for Scottish music -"

Yeah,that's an odd one in view of the love of piano and chromatic button accordeon. It's often used to object to the EC's use in Irish music as well - while complaining that a DG melodeon is too rhythmic and that only a BC can provide the smoothness and correct ornamentation (as if fiddle ornamentation was correct for accordeon).