Despite my earlier statement, I'm wondering... are state killings of that nature really wrong? I mean, separation of church and state is just a blip on the historical timeline. Back then heresy was essentially treason, was it not? An inquisition was primarily a defense of the peace of the realm since not only would heretics lead people into apostasy but most rulers may have thought such uncleanness would bring the wrath of Heaven.
And then this combines with the Ancient Roman dictum, "Nothing can be both new and true." So basically, if you could not trace your religious pedigree back hundreds of years you were considered a subversive and probably a sex pervert, more so the more collectivistic the culture.
Of course, there have always been tolerant princes, ironically the Ethiopians pretty much saved Muhammad's life. But I wonder what their motivations were in the pre-modern world.
So even if Josaphat Kuntsevich killed Orthodox, from a Catholic perspective maybe there is nothing wrong with this (obviously it would be still be wrong if Orthodoxy is the true faith-but for different reasons). The same would also apply to the Byzantine Emperors then.
I'm not advocating theocracy today or anything like that, but in light of the fact that even God told Israel, "suffer not a witch to live," etc. perhaps the past really is "a different country" in this respect.