If you are looking only as far back as 'Protestants', you need to have another look. You are missing more than half of the Roman church's escapades.
As to whose atrocities were whose, who am I to judge between the whore and her daughters? But then, one must suppose they only knew what their mother had been teaching them for a very, very long time... So maybe that might help to affix blame.
Since you claim that the likes of the Spanish Inquisition were going on continuously after Constantines time, I expect you to produce a list.