I'm convinced that Mohammed created the religion to woo the followers of the Moon God over to his side and to provide a mechanism for conquest. Islam = obedience. I surmise that is obedience to Moslem conquest. The modern doctrine that a mosque cannot be un-mosqued is the doctrine of never undoing the conquest.
I should have changed my tag for this thread.
You need to read Prophet of Doom... In this book the author describes a theory that the reason for Islam was to take over the polytheistic shrine that contained a bunch of rocks that were supposedly imbued with the spirits of the multiple gods that they worshipped at that time.
Mohammed was in line to inherit all this (and money and power) but he was sold off by what remained of his immediate family.
Allah by the way is a piece of black rock.