Another Brit here: an elderly uncle of mine, now deceased, had a real "thing" about the North American "aluminum" rendering of the metal concerned. On the whole, distinctive American ways of speaking / writing did not bother him at all; but -- while he accepted "with his head", that "aluminum" not "aluminium" was perfectly correct for the people of the US / Canada; at gut-level, he found the North American version of the word, maddening. He couldn't explain why this particular word was such a hot button for him.
I have to admit that there's another word, about which I'm the same way. The one which in Britain is "pernickety", but on the other side of the Atlantic is "persnickety". I find the word in itself, a fine and expressive one; but the American version with "s", annoys me intensely -- strikes me (for some, or no, reason) as babyish. Looking at the thing objectively -- creating such a big deal about one letter, makes no sense at all. These prejudices which we sometimes entertain about stuff of this kind, are totally irrational -- we just, bizarrely, somehow get them.