As well they should.:)
From http://en.wikipedia.org/wiki/Scotch-Irish_American
English author Kingsley Amis endorsed the traditional Scotch-Irish usage implicitly in noting that "nobody talks about butterscottish or hopscots,...or Scottish pine", and that while Scots or Scottish is how people of Scots origin refer to themselves in Scotland itself, the traditional English usage Scotch continues to be appropriate in "compounds and set phrases".[12]
In the Ulster-Scots language (or "Ullans"), the Scotch-Irish are referred to as the Scotch Airish (o' Amerikey).[13]