To help it along, I've been (childishly) taking note of the name calling I come along when reading these older theologians. Here is Luther's Biblical justification:
I have snapped at my opponents, not because of their bad morals, but because of their ungodliness. Rather than repent this in the least, I have determined to persist in that fervent zeal and to despise the judgment of men, following the example of Christ who in his zeal called his opponents "a brood of vipers," "blind fools," "hypocrites," "children of the devil." Paul branded Magus as the "son of the Devil ... full of all deceit and villainy and he calls others "dogs," "deceivers," and "adulterers." If you will allow people with sensitive feelings to judge, they would consider no person more more stinging and unrestrained in his denunciations than Paul.