The speaker is caught in a contradiction and knows it. They talk loudly, like a rebel who refuses to fit in, yet what they really want is quiet. That gap between the voice and the wish sets up the poem's gentle self-mockery, which the title, "April fool," seems to underline.
The middle stanza turns darker and stranger. The speaker's "tune" belongs to "night and knot," suggesting something tangled and private, and the swearing at "all the roaches in the world" feels like an irritable outburst at something small, endless and impossible to get rid of. In the last stanza the speaker calls themselves "a fool" for expecting order, setting that wish against "gentlemen of reason," who seem calm and sensible in a way the speaker is not.
The mood is wry, tired and a little restless. There is humor in the grumbling, but also loneliness, as someone admits they can't quite tidy their own mind or the world.