It's quite simple. In any monolithic society, like those in olden times, there was no seperation of church and state. Heresy and treason are not only the same thing, they are intellectually indistinguishable.
Has the RCC ever abrogated Unum Sanctum? If the entire world should become subject to the Pope would you defend the execution of heretics?
But it is absolutely true that in a state such as that, heresy is treason. And treason has always been a capital offense.
And the RCC still strives to see that state?
Why would it?
If the entire world should become subject to the Pope would you defend the execution of heretics?
Not gonna happen. So don't worry about it. The cat is out of the bag. The cream is in the coffe. The eggs are scrambled.
The only way the world is going to become subject to the Pope is voluntarily.
SD