The speaker is fed up with people who whip up fear and shout about it. The poem's title promises an attack on angry, abusive language, and the poem itself becomes a small act of that kind of language, turned against its target. Those "demanding we begin to fear" are described as singing "their own charge," as if they are only performing their own accusation back at themselves.
The images are dismissive and a bit comic. These voices invade "like an army of clerks / weary of life," which suggests menace that is really just tired, bureaucratic routine. A fuss, "much ado," makes an echo and then inflates it into a "salvo," a burst of gunfire. Noise feeds on noise.
The ending is the heart of it. The speaker wishes the noise would "die in it," consumed by its own blast, so that "the quiet come home safe." Quiet is treated like a person returning from danger. The mood is weary, sardonic, and longing for peace.