Did he offer an explanation as to why photographing the church is 'forbidden'?
I might understand with interiors that there is the matter of private property - albeit public private property. But forbidden is a strong word.
I was once photographing an Old Rite Russian Orthodox church here in Sydney. It was brand new and had glistening gold and silver onion domes which is all very unusual in Sydney. I was being anything but sneaky since I was shooting with an 8x10 Sinar. I was in the street, on the other side of the road. A senior cleric came rushing in his robes across to me and told me that I could not photograph the building. A discussion ensued and it was his belief that taking pictures contravened the second Commandment. The building was built to the glory of God and so, in effect, I was making an image of God.
It was all very amicable and he asked if he could look through the camera - he had never seen one before - so I lifted the horse blanket and he huddled under. He was gobsmacked. He then turned and asked me if I could photograph the entire building for them to use in a calendar for sale.
It seems that the second Commandment can prove quite a movable feast.