Uh, it's actually quite deniable.
Refusing to participate in state religion was part of civil legislation since pagan times. The Christians were prosecuted and executed--for what again?--for refusing to offer incense to the Emperor and to participate in the state cult. Theirs was a religious crime but it was prosecuted in the civil arena.
Then the Empire became Christian. The various northern barbarians adopted Christianity as well. The civil law about Roman religion now was simply transplanted to Christianity: so heresy was made illegal.
The trouble was that dukes, princes, and magistrates were *not competent* to judge cases of heresy. They could trump up a charge of heresy based on very flimsy evidence. So the Church decided to reform this system by demanding that *it* do all the fact-finding and render its official judgment in heresy cases. This was the Inquisition.
This is crucial to understand. The Inquisition, as far as I know, executed no one--an if you read the trial transcripts in those cases where people were found guilty of obstinate heresy, you find over and over again the line "and he was handed over to the secular arm to be burned." I.e. it was NOT the Church that was executing people--it was the state.
This is not to say that the Church was completely blameless in the Inquisition. There were problems with the system, and that's why it was dismantled. Heck, Joan of Arc was made a saint after she was burned for heresy.
But the Inquisition was not--as the modern parody makes it--some Church-sponsored persecution of heresy. It had its germ in the reform of a real legal problem and was actually far more temperate and fair than the secular courts whose jurisdiction it replaced.
This is crucial to understand. The Inquisition, as far as I know, executed no one--an if you read the trial transcripts in those cases where people were found guilty of obstinate heresy, you find over and over again the line "and he was handed over to the secular arm to be burned." I.e. it was NOT the Church that was executing people--it was the state.
You're arguing that because the state was doing the executing, the Church (Pontius Pilate-like) had clean hands?