Final answer:
The “principal breeders” refers to Catholics in Ireland, and the “good Protestants” refers to Protestants who chose exile over paying tithes against their conscience.
Step-by-step explanation:
The excerpt from Jonathan Swift's “A Modest Proposal” refers to the “principal breeders” of the nation as Papists, which is a term Swift uses to describe Catholics. He is critiquing the prolific birth rate among the Catholic population in Ireland, which was a Protestant country at the time, as well as their political alliance with the Jacobite cause (the “Pretender”). Meanwhile, the “good Protestants” in the last sentences denote those Protestant individuals who chose to leave Ireland rather than pay tithes to an Anglican church, which went against their religious beliefs.