There's got to be a fallacy in here somewhere. But it is a weapon that is kept under glass, and should only be employed with trembling. Un holy mockery is self-destructive because it proceeds out of a heart unswept of its own abominations. Rather than turning inward for self-examination, unholy mockery turns outward and focuses on the sins of the other guy. Dime-store godliness rides again.
Mockery is only holy mockery if employed by someone who is trembling at their own sin.
And we have enough sin of our own to keep us prostrate before the throne of grace well into eternity. No, we deceive ourselves. We may mock pietists for their overscrupulousness, but when we mock God , judgment descends from on high. First, we must understand that contrary to the opinion of some, Pietists did not tumble out of some space ship in the Seventeenth Century. Not much here to take issue with.