People ask what you do for a living precisely because it does place you in a box.
Fairly or unfairly.
But also, people are terrible at showing interest in others, and asking what people do for a living is just the most common and easy question to ask.
What you do for a living will be asked before what you enjoy, where you've been, what are your goals, what were your childhood dreams, where do you come from, etc?
Just about any truly meaningful question that gets to the heart of who you are will only be asked after how you make your money.
The question itself might not be terrible, but I suspect many take issue with when it is asked.