The irony is that the speaker seems to care, but in actuality his suggestion shows that he does not see the poor as humans and really does not care about their plight, or he would not suggest selling their children to be eaten by the rich.
Another irony is that the passage was intended to make people aware of the plight of the poor and their responsibility toward it, but it is told in Stephen Colbert-style satire, pretending to be in the poor’s best interest.
I also find it ironic that this lovely tongue-in-check essay seems to also get a jab at Americans in. The passage manages to satirize Ireland, England and American at once.