What does "A Modest Proposal" have to say about poverty and why does Swift use canibalism as the metophor for his satire?

In "A Modest Proposal" biting satire is used to point out the cruelty of the British who gave jobs only to the British and cruelly taxed the Irish, causing poor Irish children to beg in the streets and starve.  Since the British are figuratively "eating up" the Irish, in order to solve the problem of these Irish children  living to starve on the streets, Swift suggests that the British just eat the babies while they are young and tender.  If the Irish could sell their babies for food, they would no longer starve themselves and their children would be spared dying in the streets.  Overpopulation and unemployment would be solved, adds the calculating speaker who provides statistical support and specific data about how many children could provide food for the wealthy.

With his satire, it is clear that Swift places much of the blame for the poverty of Ireland upon its wealthy British landlords.  His speaker is rational and calculating in order to show that these qualities are dangerous when taken to an extreme.  Instead, common sense and compassion should be exercised, Swift desires to point out by his shocking satire.