"I get the impression that you like to play semantics."
You are the one that doesn't believe in the dictionary definition of reality.
Semantic spoons are necessary when we are dealing with liquid truth.
Does your speculative narrative expresses your disdain accurately?
"Separation of church and state would not be necessary if everyone believed in the same system. Where it becomes necessary is when there are an unlimited number of belief systems, all claiming to be the true belief system, so which one gets to be the state system?
Whichever one is chosen, its not going to be one that everyone believes in, so in order to stifle opposition, the adherents to the chosen belief system will use the force of the state, (government, police, army etc), to try and enforce this belief system on everyone.
We can see this in action in countries that have no separation of church and state, such as islamic nations.
These are brutal dictatorships, is this what you would want for your own country? I wouldn't.