I'm sure there are times when lines have been crossed. However, mocking false teachers and/or doctrines can be seen in several places in scripture.
And so it was, at noon, that Elijah MOCKED them and said, “Cry aloud, for he is a god; either he is meditating, or he is busy [“busy” means “relieving himself”], or he is on a journey, or perhaps he is sleeping and must be awakened” (emphasis mine, 1Kings 18:27).
Isaiah is extremely caustic and mocking when he speaks of idolaters (e.g. 44:12-17).
The Apostle Paul (1Cor. 11:5; 12:11) mocks false teachers in the Corinthian church and refers to them as “super apostles.” (Eminent or super “apostles” is dripping with sarcasm!)
Even Jesus mocks false teachers with incredible irony and wit:
“Let them alone. They are blind leaders of the blind. And if the blind leads the blind, both will fall into a ditch. . . . Blind guides, who strain out a gnat and swallow a camel!” (Matt 15:14; 23:24).
Thus, mocking false teachers and/or doctrines is not ungodly per se. Perhaps we should ask: What is the purpose, intention, motive or merit of the specific mockery in question. Does it instruct or does it merely wound?
Even so, one should follow one’s conscience in such things. If one feels personally convicted, one should not engage in mocking false teachers and/or doctrines. At the same time, such a one need not issue a blanket condemnation of all others who think differently.
We should not elevate our scruples above the standards of scripture.