You have ignored one whole clause in that verse — “as many as do NOT worship the image...”
Therefore, NOT one religion.
One officially sanctioned religion, which the text clearly describes, and not in the sense of no exceptions. Just that the exceptions will all be illegal at that time.
I haven't ignored anything. You obviously ignored the fact that those who don't worship the beast are killed. In addition there are those who are atheists who will not worship either. I would also challenge you to show that those who are killed during the tribulation period are not simply resurrected as Lazerous was. They are not shown to be part of the bride of Christ who have been with Christ for seven years by the time the "sheep and goats" are separated.