Everything about this New York Times story about people asking dates about their credit score is icky and horrible and obviously if you're out on a date with someone you shouldn't ask about their credit score.
That said, if you're pursuing a long-term relationship with somebody it is relevant. If you're married and want to get a loan to buy a house, for example, banks are going to want to know about your spouse's credit situation even if you're maintaining separate finances.
If there's a real scandal here it's how slipshod the credit score process itself is. I recently got a mortgage to buy a new home. When I started the process I had an excellent credit score. By the time it was finished, my score had slipped substantially because the ratings agencies mark you down for having a large number of recent inquiries. The logic is that lots of inquiries are a sign that you're running around town desperately applying for loans. But what I was actually doing was prudently shopping around with different mortgage lenders to find the one with the most attractive terms. Apparently it's possible in these circumstances to get in touch with the raters and contest their bad marks, in which case people with a reasonable explanation (like me!) will get their scores put back up again. It's kafkaesque, but since the credit raters don't actually work for you they have no incentive to provide decent customer service.