The Hagia is a Christian temple. It was originally built for this purpose. There is no other reason for it to be anything else, apart from a museum (which a lot of churches around the world are)
The Turks have no right to even enter there. In fact they have no right to be in Constantinople (Istambul) which they illegally invaded and occupied some 600 years ago. Constantinople was a Eastern Roman city which was brutally taken over by the Ottomans.
The Allies didnt finish the job after freeing Vienna and Budapest, (later Bucharest and Sopia were freed from the brutal Turkisk occupation) But the Christian Allies should have driven them out of Europe and they could have easily done that even in the late 1600s (even though Sobieski had no further interest after freeing Vienna and leaving)
