As one with allergies, like one of the Obama kids, the chances of finding an appropriate dog at a shelter is next to nil. It took me over a year to find Scruff and that was just dumb luck. Of course the Pres would have more contacts and pull than I do..but still.
How much worse would it have been for him to get a shelter dog only to have to give it up becuase a daughter was allergic.
I think his choice was very responsible.
My concern is also with the potential 'instant popularity'of a challenging breed.
I hope it doesn't happen, but I don't have much faith in humans.