Spoiler alert! This poem has two speakers. Yep, two. First, there's the dude that spots this little kiddo freezing in the snow and asks him, "hey, what's up with that? Where are the 'rents?"
Then, there's the kiddo himself. Much of the poem is made up of his speech to the poem's actual speaker. So we get the meat of the meaning in the voice of a little kid, who's forced to labor in other folks' homes in exchange for, well, not much.
Why that change? Why not just stick with the original guy, and tell the chimney sweeper's story through him? We think Blake was up to something.
Remember, these kids didn't have much of a voice. They were sold off when they were quite young—sometimes four or five years old—to work hard with no compensation (other than food and shelter). Maybe, just maybe, Blake wanted to give those kids a voice, and allow the chimney sweeper to tell his own story.
Okay, so if that's the case, then why wouldn't he just write the whole poem in the voice of the chimney sweeper? Hmm. Fair question. But, as it turns out, Blake already did just that—with his Songs of Innocence version of this poem.
In this Songs of Experience version, the choice of having an adult speaker, looking down on this little tyke is very effective. We feel complicit in this man's participation in the chimney-sweeping system. We, too, are looking down at this kiddo, wondering where in the world his parents could be, and feeling pretty broken up about the whole shebang. And then it hits us—this speaker (and all the other passers-by), probably have some very clean chimneys…