It.....that he wanted a nonsecular setting.
But for over 100 years, major policy talks were given from this location . It is well known - esp in DC.
Obama people knew what was coming, and didn't want a cross with "Jesus of Nazareth King of the Jews" in the back drop.
As bothersome as that is, the real issue came when Georgetown abandoned the lat vestiges of its catholicity by reciprocating. They denied their faith and covered it up in order to get the president who eschewed Christianity to speak there.
I know you buy the Obama claim "we wanted a nonsecular background", but they were knowingly telling a catholic (just barely maybe) institution to remove their religious nature or they'd take their ball elsewhere and they won.