It doesn't upset me, for one, but it's part of those niggling little things that have a cumulative effect. In itself, it's nothing — a footling detail. But you add them together and you end up over many years with a mountain of bias. One grows weary of it.
It's only United and Liverpool who benefit from this kind of thing. The United/Liverpool mythology spills over into Europe, too. Recently I've been watching City's matches, and one or two others, on RMC — the French sports tv channel. I turn the commentary down completely (and have Manchester Radio on in a second window, to get my commentary) because they're pig ignorant of the actual history of English football (which they only started to pay attention to with the invention of satellite tv), and because they've got their tongues so far up Liverpool and United's fundament that it's just sickening.