The other possibility is that these witnesses are credible, but capable of being smeared into ineffectiveness.
Either way ... without a witness befor a congressional committee .. this is just another Friday/Saturday doc dump.
If true and that is a big IF, perhaps he did it to gain access to Mecca and other Islamic circles. No one but a Muslim can enter Mecca/Medina. In Saudi Arabia, they issue special identification, an igama, that identifies one’s religion. It is checked at all entry points to Mecca/Medina.
Obama advisor John Brennan speaks about the beauty of Islam (youtube video)