I don't object to being called an Irishman. I don't think Frenchmen, Welshmen, and Englishmen object either.
I think it's just a way of demonstrating power, to force people to change how they speak for no real good reason.
Or of testing whether they have the power. Remember the recent effort to ban peanuts from being handed out on airplanes? I've noted the decline of peanut packages to the point where I'm about to carry my own aboard.