Perhaps I simply have a warped sense of humor, but I thought Schow's story was funny (and yes, I'm disgusted by roaches). What I particularly enjoyed by the story, other than being entertained by the quirky narration, was the underlying message, at least the underlying message that I perceive.
It is this: you've got a curmudgeon-y Vietnam vet who has a really negative view of everyone and everything around him. And yet he, like everyone else in the story, is nothing but a product of the sort of depraved environment Schow has created. When the protagonist, at the end, hollers in the street like a mad man, it became clear to me that he was, like everyone else, crazy, especially crazy.
The ending, I thought, for the story was perfect. The cockroaches pouring out from his prosthetic leg was the perfect symbol to convey that he's no different than everyone else around him. Cockroaches, to humans, are all equally disgusting. They are homogenous in this regard. As were the characters (sort of) in Show's story.