It is along the same lines as people asking a combat vet "Did you kill anyone?"
Sometimes curiosity overcomes propriety.
Whenever I tell someone that my husband is in the 82nd ABN, that is almost invariably the first thing out of their mouth...unless I'm talking to a military veteran or family member of a veteran. It's revolting that they think of my husband that way before anything else, especially considering that the folks who do it love to state how "non-judgemental" they are. I even had my brother ask me, in a state of utmost curiosity, at the dinner table one night, when I visited home. He's almost 30, BTW, so he's definitely old enough to know better.
The fascination of some people with the intensely personal and private is indicative of our loss of manners and respect for others.