to be fair to the south, "coke" is more of a nickname for "coca-cola". i mean eventually it became Coke™ but i think that's because of capitalizing on the nickname
what do you want
coke
what kind
coca cola
sure i get annoyed too but it wasn't until the 40s that this was trademarked. i would wager that soft drinks were "coke" in the south before that and they've been teaching their kids evolution was false since forever; they ain't changing this neither