Yes. There is a dress protocol for women visiting the pope in his private residence that is normally respected. It is optional, not mandatory. The fact that Mrs. Obama chose to follow the protocol, is indicative of her respect for this office.
US first lady Michelle Obama, leaves the Vatican after a meeting Pope Benedict XVI with President Obama, Friday July 10, 2009. The US President sat down with Pope Benedict XVI at the Vatican on Friday for a meeting in which frank but constructive talks were expected between two men who agree on helping the poor but disagree on abortion and stem cell research.
Or is it her upbringing in other religions in which the woman is secondary to the man. In the pictures I saw this morning she was about two steps in back of the Pope and her husband. Mindeast protocol? Judaisn protocol? Not like the pictures of Laura Bush. Made me wonder.