So God does not show favor as He wills?
Or is there no God?
What Calvin did (and by extension, what all who claim to talk for Him do) is to place himself (Calvin) in the position of God and to mete out punishments as he (Calvin) saw fit. This is the height of hubris; God does not need mere mortals to punish those with whom He might disagree. "Vengeance is mine, says the Lord."