I get it OP.
I also get the slightly separate but very much related issue of this question being othering when people are actually from elsewhere.
Both things, to me, boil down to a really thoughtless desire to pigeonhole and stereotype. There is no place for that. I’ve had this question a lot and it’s never been anything but stereotypes even from seemingly broad-minded people. Occasionally, as a PP has said, it’s been an outright excuse to be “anti” the perceived attributes of my background.
To those saying “get over it”, can you imagine the pressure and anxiety this sort of question creates when you’re from elsewhere and it’s 50/50 whether someone says something that is at best banal or whether, unprompted, they start to trot our ignorant political/racial stereotypes.
It’s also way too personal a question for superficial conversation. I really hate it and, I’m afraid, judge harshly when relative strangers ask it. I hope it will become outdated in the same way we don’t (usually!) now ask “any kids/why not/having another soon?”. It’s as personal as an icebreaker and you’ve no idea of the backstory.
To all those who have said they try to ask wider questions like “where did you grow up”. That’s much better and leaves a lot of room. I always appreciate that.
To those who think “where is your accent” from is an acceptable alternative - please don’t. It’s like saying “it’s instantly obvious you’re different/a foreigner” and is especially off-putting if the person being asked has English as a second/third etc language, because they’d have worked hard on it.
You don’t know what history people have with being welcome/unwelcome, don’t stir it up. If all is well and people are super comfortable with their dual heritage/background, as some PPs are, great, and they’ll tell you in time. But be aware that the upset you may cause to someone with this “innocuous” question will far outweigh any ice-breaking you may do if it lands well.