Albert Barnes Commentary 2 Kings 14:21

"And all the people of Judah took Azariah, who was sixteen years old, and made him king in the room of his father Amaziah." — 2 Kings 14:21 (ASV)

All the people of Judah - The words imply that the conspiracy was one in which the general population did not participate. There was no confusion or trouble as on the occasion of the murder of Joash. Azariah (“the strength of Yahweh”) and Uzziah (“whom Yahweh assists”) were simply variants of one name.