They are one hundred times more insecure about Assyrian Churches. The reason is since Islam was derived in part from the COE. Mohammed's Mother was Christian and he was even taught a little bit by the Assyrian monk Bahira. Whatever is in that Church they want to hide fast.
Yeah, the problem is that Muslims don't want to admit that there were ever any Christians in Arabia. They are afraid that one day some of their people will realize that their "prophet" was influenced by deluded Christian teaching. Its a shame that they are not letting anyone see it. Knowing Muslims though (and especially the Sauds) they will probably destroy it, or at least destroy the crosses and cover up the existence of Christianity in Arabia.
It is a beautiful church. I especially like this cross that is in the doorway: