Although satire's purpose is to be humorous, it also allows an author to show the foolishness of a certain populous. In this excerpt, by satirizing religious conflicts, Swift presents religious disputes in England as petty and frivolous.
If this is not the excerpt you are to (the one between Catholic France and Protestant England), use the hook-transition-thesis. You can copy the first sentence and then talk about the petty acts of the ruling class or the absurd (but humorous) solution Swift offers.