What is the acceptable number of people murdered to keep in teaching with the Church? The Inquisition had many thousands burned and tortured but it may not have reached millions.
"Many thousands burned and tortured" -- The total number executed under the Spanish Inquisition was about 9,000 over 350 years, according to secular historians. That's twice the number killed in a single month in Soviet Russia in the first years after the revolution.
Revulsion against the excesses of religious persecution led to the Enlightenment, which undermined the prestige of the state churches. To a considerable extent, the reaction led to anti-clerical governments in revolutionary France, early 20th Century Mexico, and Spain before the rise of Franco. The Enlightenment ideas helped to foster the rise of Marxism, which led to the deaths of over 100 million human souls.