I think humans have a default toward tribal thinking. We view "us" as superior and more cherished than "them". I don't think most people will agree that they, personally, are prone to it; but it shows up in a hundred different way in life. I spotted that thinking in myself when I saw that the next oracle wasn't a terrible foreign enemy, but our Jerusalem. This should remind us that when we act like the enemies of God, we shouldn't be surprised to find ourselves on a list that includes those we're acting like.
It seems like this chapter is related to the events immediately before, during, and/or after the reign of Hezekiah.
Isaiah has been prophesying about the end of Israel as a cautionary tale for Judah. We've seen that Assyria will be the instrument to crush Israel and then come for Jerusalem, sending Judah's villagers fleeing in fear. But the Lord will deal with Assyria and raise up a remnant of his people.
Isaiah begins with his indictment of Judah's behavior and a prophesy of their future which is also a parallel to the end times. Then we flash back to read about his calling. Now we are back in his historical timeline with the kings of his time.
Chapter 3 ends with the proud, seductive daughters of Zions being taken and abused as slaves in this time of terror and desolation. Chapter 4 opens with women so desperate for a husband, they agree to support themselves.