I'm choosing to discard it precisely because it isn't relevant, as I said. When and where a word was coined implies nothing about what languages it is and isn't a part of today.

Indeed, but “soccer” is part of American English today. Why should we stop using a word just because people in a different country stopped using it? Is your argument really that we should speak identically to people in England, because the language happens to be called “English” ?

I think you should either conform to English English, or treat American as a first-class language of its own (and e.g. start offering translated websites).