How can you possibly not understand? You really are flummoxed about people who devote themselves to supporting their families economically and thus invest great energy into that pursuit?
That’s like going to the Olympic Village, among all the athletes, and being unable to understand why athletes ask each other “What’s your sport?” They are in the Olympics, man! They put everything into getting there. Ask them about their obsession, for crying out loud.
And ask me about how I am trying to make it in the world. I am happy to talk about it! Why aren’t you?
On the Internet, where passive aggressive behaviors reign supreme, "I don't understand" is code for "I dislike"
The people that say it about mundane things like asking what someone does for a living, know full well why people ask it.