Some people obviously have less extensive vocabularies than others.
It's a shame if your stories were rejected due to their limitations.
That's all it is. The ones with the most problems with it are the "'MERICA, FUCK, YEAH!" xenophobes. You know, they type who say over the internet to people in other countries: "I'm sorry, I can't hear you over all this FREEDOM!" and don't feel they should have to use Google for anything they don't understand.
Meanwhile over half the country does an embarrassed face-palm.
Can't really explain it except maybe in-breeding and blinders fused to their temples.
Only thing I might like is the realism that if the characters are from the States and it is set in the States, use the American spellings because it'll sell the fantasy better. That's all. Kind of like not having Brazilian football players refer to their friend's mom as a "soccer mom."