You're right of course, Roger, but underneath all of the bizarre nature that goes on in showbiz people's lives (not all of it of their making - the media demands its diet also), you do have to ask the basic question once their fitness to adopt and look after a child is granted - do they actually want children?
If the answer is yes, then they are surely as entitled to adopt as anyone. If there was evidence to suggest that any of these celebrity adoptions were ephemeral affairs (have any of them tried handing back the children yet?), then you would have to question more deeply, but I've not heard of such cases. I have, on t'other hand, seen a number of cases first hand where, given the power to do so, I'd have locked up the natural parents (after surgery to make sure their status as such could never be reinvoked), and gladly handed over their offspring to the nearest celebrity demonstrating a willingness to show them even a modicum of genuine love.