Yea, it sounds just as pointless and stupid when you mothers of bi-racial/multi-racial children do it.
Why the hell do parents of mixed kids feel the need to constantly display their children as if they are in possession of some rare life form? Who the hell cares that you have mixed kids?! Why must we play "guess which race my kid is" games with you?! Why must the first words that come out your mouth when someone compliments your kid be "thanks, she's mixed with..."
When someone compliments my child, I don't respond with "thanks! She's black! "
We get it, you have mixed children... No one cares.