Simply put, there are some pretty unattractive characters walking around "The Waste Land." The worst of all might be the two-thousand-year-old Tiresias, with his "wrinkled dugs" (228); but the pimply-faced "young man carbuncular" (231) might give the prophet a run for his money in the Ugliest Eliot Character pageant. Eliot might talk a lot about sympathy and compassion, but he's more than willing to draw a direct relationship between moral and physical ugliness when it comes to stuff he doesn't like. Eliot focuses on people's appearances constantly throughout this poem, and always does so to convey his larger ideas about spiritual beauty and ugliness.
By using people's physical ugliness to show their moral ugliness, Eliot undercuts his own message of compassion and sympathy
In economic terms, ugliness for Eliot is always just a shorthand way of saying "working class."