They're casting a spell on humanity using a number.

The illuminated ones are casting literal magic spells on people. One of the ways they do it is by putting a certain number in peoples minds. Questioning or denying that number weakens the spell. Same happens if you add to that number or subtract from it.

The magic spell only works if we think of that number just the way it is. In other words, the number has to be real in our minds.

If everyone woke up one day believing the number is incorrect or changed the number the spell is broken and their fire ritual becomes invalid; this will cause the illuminated ones lose their power and everything they gained by using that number magic. That's what they fear the most and that's why they are trying to outlaw questioning that number.

If you know what number I'm talking about, stop thinking about it or change the number in your head.