Exploiting the poor
The novel is predicated on this ironic observation, that those at the bottom of the social hierarchy are the least able to fend of those who would exploit them. That means that the landlords in this community can abuse them financially (the community is mostly unable to afford owning a house, so they are subject to landlords). The poor have least to lose, but they get nickeled and dimed out of what little they own.
Passion and success
There is a poet in the story called Willie who is one of the points of view in the novel. He sees the world through the lens of his passion. He has suffered greatly, so much that extemporaneously, he began writing poetry, and now has found much hope in writing lines about his life, his struggles, and his observations about the world. This also comes at an ironic cost, because he longs for success in poetry, but he doesn't have the influence to get traction with his writing.
The abuse cycle
The novel observes a few ironic aspects of domestic abuse. Typically, the ones who are abused as children do much of the abuse later in life, which is a sad irony, and ironically, the people who have the least margin in life, the exceptionally poor, are also more likely to be in abusive situations, because life is beating the family down, and they are unable to escape each other, because they don't have access to social mobility. The irony is tragic and steep.
Hope and progress
There is an irony about hope because the more a character wants to make progress, the more they have to wrestle with their dilemma of hope and hopelessness. For instance, Luther wants to leave, and when he comes home, his house has burned down. So, that is ironic, because he both doesn't have a place to stay (he got his wish about leaving, perhaps), but it didn't necessarily help him at all. Hope is a double-edged sword, it seems.
The stakes of community
The irony of community is that to be alive, one needs to belong in a community, basically. But, community is not just a thing to be exploited or gained from. Ironically, community comes with serious risks, because people are volatile, and at the bottom of the social hierarchy, there is the problem of being taken for granted by need, untrustworthy people. Community is a risky endeavor, but also a necessity.
