The Catholic Church threatened to kill Galileo. A permanent stain on the Church.
WRONG. The Catholic Church threatened to torture Galileo.
Torture actually has a procedure. First, the victim is threatened with torture. If they do not comply, the victim is taken into a room and shown the instruments to be used to conduct the torture. If they still do not comply, a professional wielding these instruments would conduct the torture, usually publicly. If the victim STILL does not comply, then, and only then, is the victim put to death.
For Galileo, a man well aware of the capability of such instruments of torture and what they could do, complied at the mere threat of torture. He did not need to recant his publication, was required to state the Church was the highest authority, and was placed under house arrest for the rest of his days and did not go against the Church again.
Others within the Catholic Church, inspired by Galileo and others like him, began to question the scripture as interpreted by the Church. Even priests, cardinals, and bishops were raising questions. THAT was when the Pope invented the Inquisition. Very nasty stuff. THAT was a stain on the Church.
Out of it came Lutheranism, the Church being forced to recognize science at least on some level, and a few more atheists. Christianity fractured into a chaos of different religions, each enhancing some aspects of the gospel and tending to discard the rest.
But God and Christ are not the authors of chaos. How will this resolve?