The scene in A Modest Proposal is pretty dismal. You're walking through the streets of Dublin when kids come pouring out of the woodwork. They're everywhere: packed into the roads and peering through cabin doors. And don't forget the moms. For every Brady Bunch, there's a desperate mother blocking your way. Before starting in with the satire, Swift wanted this image locked into his readers' minds.
In A Modest Proposal, the people are as much a part of the setting as the Irish countryside. The narrator's whole point is that you can't enjoy your trip if every inch is clogged with children. He wants the reader to imagine walking through the "great town" (1) of Dublin and being forced to confront poverty. It's everywhere, and it's not going away.
Swift's Ireland was suffering through a terrible famine in the 18th century, made even worse by crowded conditions and freezing weather. And the situation wasn't getting better. Only ten years after Swift penned A Modest Proposal, an event known as the Great Frost froze the sea and wreaked havoc on Ireland. Think of it as the winter they're always talking about in Game of Thrones.
In the middle of this mess, some lucky sons of guns managed to claw their way to the top of Irish society. Some of them were merchants, some of them were landlords, and all of them had their ancestors to thank for winning wars and generally rocking at life (source).
Of course, the poor had to exist to make life easy for wealthy landowners. Poor Irish families got paid next to nothing and had their rents increased at random by greedy landlords. At the same time, farming was out of the question because the poor Irish weren't allowed to "build houses […] nor cultivate land" (7). British restrictions on land use took care of that, making a pretty big dent in the Irish agricultural industry.
Let's add a little bit of class-based tension to the mix. Many members of the wealthy class were Protestants who lived in fear of Catholics taking power. They were particularly paranoid because former king James Francis Edward Stuart had recently been stripped of his throne due to his Catholicism. And you guessed it: the majority of the poor Irish were Catholics (source).
The way Swift saw it, England was twiddling its thumbs while the Irish starved. The way England saw it, ruling over a rebellious Ireland was no peach of a job (source). One thing was for sure: the numbers-crunching English policy towards Ireland angered lots of people who felt that the situation was becoming dire. Swift wasn't letting the Irish off the hook, but he certainly wasn't pleased with the motherland.
You didn't think Ireland would have a major economic crisis without old Swifty giving a piece of his mind? By this point, Swift had been sitting pretty as Dean of Saint Patrick's Cathedral for over a decade (source). He'd also written Gulliver's Travels, which earned him a little more celebrity status as a satirist.
Still, the same firecracker who wrote dozens of pamphlets and tracts on Ireland's plight was raring for a fight. He knew that England and wealthy Irish landlords didn't care one whit about what was happening to the poor. Check it out:
But as to myself, have been wearied out for many years with offering vain, idle, visionary thoughts, and at length utterly despairing of success, I fortunately fell on this proposal, which […] can incur no danger in disobliging England. (30)
Swift makes it pretty clear that Ireland is the only country that could benefit from selling kids as food. He says, "I desire the reader to observe that I calculate my remedy for this one individual kingdom of Ireland, and for no other that ever was, is, or, I think, ever can be upon earth" (28).
There you have it, folks. Travel to Ireland for the fine scenery and the opportunity to sample unusual delicacies.