The speaker of "Comedian" is wary of anything that claims to be serious. In the first lines, they say they doubt the "verdict" that solemn things hand down, as if gravity alone gave something the right to be believed. The title adds a twist: a comedian is someone who gets away with saying what others can't, and the speaker seems to claim that stance.
The middle lines are harder to pin down. Truth is pictured as a pulpit, a raised platform for preaching, and the speaker suggests it can be used "to protest in," so even a place of authority can be turned against itself. Then comes the firmest statement: no sins confessed "to the state," and no sorrow offered to "my midnight."
The mood is dry, defiant, and a little lonely. The speaker guards their private grief and guilt, refusing to perform them for public institutions. Judging by the tone, humor may be a way of keeping those feelings protected rather than dodging them.