how does swift use irony to satirize anti-Catholic feelings?

Almost every satirical work in this collection deals with the matter of religious excess in some form, especially A Tale of a Tub and “A True and Faithful Narrative.” A Tale of a Tub portrays three brothers, who represent the three branches of Western Christianity, as all naturally licentious and without true religious conviction, having only outward appearances of conviction. “A Faithful Narrative,” too, portrays a largely sinful town thrown into displays of repentance when the people believe a comet is coming. “A Modest Proposal” mocks anti-Catholic religious prejudice, as the narrator calls the Irish babies “papists" because they are Catholic.

"A Modest Proposal" purports to address the problems of poverty and overpopulation in Ireland with a simple economic solution: the Irish should eat their babies when the infants become one year old. While some serious alternatives are provided, the piece at least involves a humorous method of getting people thinking about the real issues and how they might be solved in a way other than cannibalism.