Certainly, O'Connor criticizes prejudice in all its forms. The grandmother has a great deal of prejudice, mostly against people that she feels do not behave as proper ladies or as "good men." This skews her priorities and values a great deal, though she is unaware of any problem with them. In this way, O'Connor uses dramatic irony—when the reader knows more than the character(s)—and dramatic irony is often symptomatic of satire: a genre which aims to point out human flaws and attempt to compel us to change for the better. For example, the narrator seems to speak with the attitude of the grandmother at times, such as when the narrator describes "the children's mother, a young woman in slacks, whose face was a broad and innocent as a cabbage and was tied around with a green head-kerchief that had two points on the top like rabbit's ears."
It is notable that she is never named, and she is introduced as being a woman who wears pants, something which would likely offend the grandmother's ladylike sensibilities. Later, she is described as "the children's mother [who] still had on slacks," as if this were the most important thing about her (which, to the grandmother, it likely is because it shows that she is not a lady). At the same time, however, the grandmother is clothed in a sailor dress with a navy hat and some artificial flowers so that "In case of an accident, anyone seeing her dead on the highway would know at once that she was a lady." The grandmother's prejudices against anyone who isn't a "good man" or a lady or who isn't the offspring of "good people" is satirized through her use of dramatic irony to make the grandmother seem all the more out-of-touch.