The Proposer is our main guy, since he's behind the whole plan to save the Irish from starvation. Okay, his ideas might be a little bit misguided, but he's got his heart (and stomach) in the right place. He shows the reader why the hardhearted landlords are Ireland's biggest problem.
We've also got the poor Irish people, the unsung heroes of A Modest Proposal. They (try to) support their kids and keep it together enough to survive. Swift is totally rooting for them to make it, despite the Proposer's harebrained solution.