In Sandburg's "Chicago" who is "they" in the section beginning in line 6?

"They" refers to those people "who sneer at this my city",
as the poem makes clear a few lines below. They are the people who criticise Chicago for
its corruption, vice and social inequalities. Sandburg replies that the evils of the
city are apparent. Yet, these too are the result of the city's working-class pride and
vitality. Sandburg does nothing to counter the accusations. On the contrary he expands
on them: as you can notice, after he mentions the accusation, he gives examples of it.
Yet, while these vices remain, they are considered next to nothing taking into account
the strengths of a city "proud to be alive and coarse and strong and
cunning.”