I've written about this a lot, but since it came up in the comments on my last post (see how I'm spring-boarding from post to post here?) I thought I'd revisit the subject.
Like many Brits, the phrase rang in my ears from the time I could speak. Saying "she" or "he" about a person when they were either standing in front of you or within earshot, induced gasps of horror and the outraged question in this post title. (And no, despite years of research, I still haven't a clue where it came from.)
Thing is, in the USA, not only do they do it all the time, - it's not even considered rude.
When you're out at dinner and there's one person taking control and giving the waiter everyone's orders it quite often goes:
"She'll have the chicken, he'll have the fish and they'll have the pasta." And then the waiter will run through the order before departing, with "OK so, she'll have the chicken, he'll have the fish and they'll have the pasta."
Just not considered anything out of the ordinary.
But when my British friends and relatives come to visit, they can barely contain themselves the first few times they experience it. Usually, they lock eyes on me until I meet their gaze and then give me the "How bloody rude is that? I can't believe she said that" look. Years ago a lovely neighbour of mine remarked on how similar to me my English friend sounded. (Big surprise, eh?)
"Oh, she sounds just like you", neighbour said, turning from my friend to me. I just laughed politely, but my friend seemed frozen to the spot. As soon as we were inside my house the friend found her words. "Did you hear what she said?" etc. etc.
Expats who are only here for a few years, - if you're raising children they're going to pick up what they hear and adopt the language and customs here. There's no point in insisting they use various British-isms if their friends haven't a clue what they mean, and there's really no point in making a big deal out of the cat's mother, when they're not offending anyone in the USA.
Just remind then they're not to say it in front of grandma next time you're back in the UK.