If you live in the US, I agree that you must use American English.
But even us people that live outside of the US/UK/related countries often got errors marked, because we used the wrong regional variant... In Europe, British English is used as a reference point, but I had a similar problem as GP.
> In Europe, British English is used as a reference point
Anecdotal counterpoint, but… I’m a British English speaker, but many of my colleagues are Continental Europeans, for whom English is their second language. Part of my job involves copy editing and, almost without exception, their output is written in American English.
No, it's due to the ovewhelming exposure to media from the U.S., mere spellcheckers oughtn't interfere with 'underground' vs 'subway', 'film' vs 'movie', 'flat' vs 'apartment', and so on and so forth.
My teachers only commented/deducted if I mixed spellings in a single essay. If a teacher can't teach someone who uses either variant they probably have a stark educational deficit themselves.
when i was an exchange student i was told that some students would have problems coming back because their english teachers would not accept the american english they would learn during the exchange year and that might reflect on their grades. fortunately i had an understanding teacher who didn't do that, but who was happy to see my english dramatically improved.
> If you live in the US, I agree that you must use American English.
Why though? I think you missed my point with the rationale for this. See below.
> But even us people that live outside of the US/UK/related countries often got errors marked, because we used the wrong regional variant... In Europe, British English is used as a reference point, but I had a similar problem as GP.
That makes perfect sense though? The point wasn't "act American because you're in America", the point was "they're trying to teach you to communicate with {whatever audience they believe you will most often find yourself needing to cater to in the future}". Obviously in Europe they deem that to be British-English speakers. In America it'd obviously be American-English. etc.
As a computer science student in England we were told we should use ‘program’ rather than ‘programme’ since that was the convention in our subject.
If I remember correctly BBC Basic accepted COLOUR as well as COLOR keywords to be more approachable to primary school children who were native English speakers.
But even us people that live outside of the US/UK/related countries often got errors marked, because we used the wrong regional variant... In Europe, British English is used as a reference point, but I had a similar problem as GP.