Is it strange that the most fleshed-out character in this poem is a stone bridge? As for the rest of the people of New York, they seem more like a mass of suits or rags, a crush of traffic lights, or a group of shadowy figures in a movie theater. The vision of identity in "To Brooklyn Bridge" is more like a vision of anonymity. We never see faces or specific features, and the class or subculture to which a person belongs is more essential than their individual traits. Of course, anonymity can be soul-crushing, but it can also be liberating. You get to stand in the shadows and watch the world go by without being bothered. The poem seems to suggest that the age of the individual has passed and the age of the democratic masses is under way.
The identity of individuals in "To Brooklyn Bridge" is subsumed by the identity of the city as a whole.
Like Prufrock in T.S. Eliot's "The Love Song of J. Alfred Prufrock," the speaker of "To Brooklyn Bridge" is an autobiographical figure that the poet does not want us to know is autobiographical.