“Scotch” is an archaic form of “Scottish.”
All these people butchering “Scotch-Irish” wear a Scots Plaid tartan, use Scots Tape and drink Scots Whisky, I guess.
“Scotch” is whiskey, nothing more, nothing less. All other references to the people of Scotland should be “Scot” or “Scots”—as the name implies—”Scot”-”land.”