Saudi Arabia is untouchable - the oil business is far more important than those hijackers. You don't need to be a conspiracy theorist to figure out why a Bush would not ever come down hard on a Saudi.
On the day after 9/11, the only planes flying from the US were those carrying members of the bin Laden family away. Now, it's fair enough to say they would have been in danger just for being bin Ladens. But who took that much care to protect other innocent Muslims from the danger they were in because of a family member? Guantanamo Bay was where they went.
Mr. Obama is not beyond criticism, as is obvious from this thread. But I can't quite see any reason to be hard on the man for trying to protect America in his way, since Mr. Bush's way was such a dismal failure.