I think perhaps American terms in British fandoms bother me more than they might bother others because I am so utterly fascinated by American/British language differences and try to find out more about them at every opportunity. Then again, perhaps they would bother someone who doesn't know many American-British term differences more, because they would just be thinking 'Why does she have a wallet in her purse? That makes no sense', as opposed to 'oh, it must be the American "purse"'.

I don't know why we pronounce 'z' 'zed' when it's on its own. 'Zee' would rhyme with 'b', 'c', 'd', 'e', 'g' and so on. It is a letterish sound! But pronounce it 'zed' we do.