The people at the first level of the City of Ancient Emperors were all of the same generation and at the Celestial Phenomenon Realm. There were naturally clashes and endless conflict. There might even be incomparably intense grand sect wars occurring.
Hence, those people below who saw the fight breaking out in the air were still very calm, not feeling strange at all. They were merely wondering why these people were fighting.
Seeing that there were a limited number of people on each side, this didn’t seem to be a war between sects. And seeing that there was only one female was participating in the fight, it seems to be a case of jealousy as well.