Have USians have recycled the "u" they threw out of "colour" and "labour"?
I think they mostly got donated to the 'Vowels for Bosnia' campaign.
I don't find anything odd at all about 'sulphur'. I'm quite sure that I'd not trigger at all on a spelling error upon encountering it. Nor the newer spelling, for that matter. "Correct" spelling is, after all, a rather new thing. Even as recently as a couple hundred years ago, spelling was much more varied than it is now -- at least in English usage. Punctuation as well has evolved quite a lot. Proper usage of, e.g., the colon, semi-colon, and hyphen is something which is almost completely faded.
I think that most Americans think that all English people speak like John Cleese, except for Cockney, and are unable to distinguish between a Burr and a Brough.