Romania looking like a theocracy. Diversity here is indeed low as hell.

Surprised to find Saudi Arabia is shaded orange. Are non-Muslims even allowed in without a special visa (i.e. them being either diplomats or contractors needed for a specific task)?

Where do you get the idea of this non-Muslim visa ? Never heard of it.

IIRC, entry was nominally banned to non-Muslims (holy land and all that), though occasionally they needed some specialists (engineers to build infrastructure and such). They would get a special exemption, which would look more like a letter from the relevant government minister than a form one fills out and gets approved by the bureaucracy.

Ah maybe you're right, regarding the two cities of Mecca and Madina. I found it weird to be the case for the whole country.