If any reader still thinks that this is a serious piece by this point, the “main objection” ought to persuade them that it is not. The writer says that the main objection to the killing and eating of Irish young is that it will decrease the population. A truly serious objection from a normal human being would be that it is morally wrong to consume human flesh on such a large scale. Furthermore, it is a straw-man objection, since the author reminds the reader that reducing the population is the overall goal anyway.
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