Everyone seems to be making the assumption that the Obama administration chose the code name "Geronimo", and I have to include you in this too, Kathryn. (Based on a bbc news report I did it myself for a while.)
But consider, the US has been after Osama since 2001, with Osama slipping across the border from Tora Bora then. Isn't it far more likely that the DIA or CIA cam up with the code name "Geronimo" then, and that after 6 years of the use of the code name "Geronimo", it would simply have been impossible for Obama or anyone else in his administration to change it?
What was the Bush Administration's code name for Osama? "Gore"?
That said, the consequences of the use of that code word are being minimized by those speaking up about it. And thanks to those efforts, more people are learning about the real Geronimo.