It's unconstitutional, right there in first nine words of 1A, even before the free speech part.
It's not that churches are excluded from taxation, it is that they are excluded from all effects of lawmaking because of religion. The laws made can only apply to non-church entities.
You can apply building and safety and occupancy codes to the structure, you can apply income tax to the attendees, et c, but it says right on the tin: "Congress shall make no law respecting an establishment of religion".
It's not that churches are excluded from taxation, it is that they are excluded from all effects of lawmaking because of religion. The laws made can only apply to non-church entities.
You can apply building and safety and occupancy codes to the structure, you can apply income tax to the attendees, et c, but it says right on the tin: "Congress shall make no law respecting an establishment of religion".