This stuff gets pretty deep. Now heaven protect your booze. It is also a comic poem. It is a poem because, well because it meets the rather wide standards of a poem. It is a comic poem because it was meant to be funny.
Relief is one aspect of humor, recognition is another.
We recognize the distorted figure in the fun house mirror as ourselves. It makes us laugh. And if you recognize someone of your acquaintance like the famous bard in the poem above, you will certainly feel a sense of relief that he is nowhere near. Years later the language poets would expand on that, ad infinitum. But for then, the fact is that agg got a laugh when ugg didn't, and the poet kept it among his repertoire.