Many Scots find the adjective Scotch to be pejorative because of it's Anglo origins. For many non-Scots, myself included, Scotch is still a viable term. If it can describe whisky and eggs, it can be used for people - all of which/whom relate to Scotland. A fuss about nothing, methinks.
On Not606, I have used the term scotch I would estimate about 2000 times. I've got a reaction 3 times. 2 of those were Dev. On The Guardian I have used the term twice, got a few reactions including a link to the wikipedia definition of scotch. That's gotta be worth a few points.
I simply pointed out that I take as much offense over usage of the word Scotch as I do being called Jock. ie None. I also pointed out that anyone who tries to bait Scots by calling them Scotch is either: A: Incredibly ignorant, probably from Essex or Kent or somewhere in the boondocks B: Attempting wummery that was old in the days of Noah Batter on everyone, choose a category first though. And remember, Stewart Lee buried this joke 5 years ago,
My wummery is as old as your jokes the difference being that my wummery makes me laugh and that's all that matters.