Israel had every opportunity that the Gentiles did not have. God gave the Israelites gifts to live a better way, but they completely failed to reflect Him.
Martin Collins, reflecting on the devastating locust plagues described in Joel, marvels that the prophet, instead of promising a silver lining on a very black cloud, affirmed that things were going to get intensely worse before they got better. Nevertheless, Joel, whose name means Yahve is God, in the middle of his prophecy, …
God will do what He must to bring Abraham's seed to repentance and salvation, including allowing crisis, hardship, humiliation, and calamity.
Hezekiah did a great deal of good and had a repentant attitude, but he was also proud and self-centered due to the wealth and success God had given to him.
Realizing that men are prone to mistakes, God commanded the Israelites to have six cities of refuge to protect those who accidentally committed manslaughter.