“For I am the Lord—I do not change. That is why you are not already utterly destroyed, for my mercy endures forever Malachi 3:6 TLB
These are Old Covenant passages. God has always been good, merciful and compassionate. Under the Old, however, God had not yet sent Jesus. God had no choice but to send judgment for sin. When He instituted the Law and sacrifices He was able to still much judgment for the sins of people.
Also, when looking at the cultures of the people's the Nation of Israel warred against and defeated to take the land were barbaric in nature. Apart from God they worshipped idols and sacrificed their own offspring at times. Was God desiring to kill humanity? Of course not, but Jesus hadn't yet paid the sin debt of humanity. Going further back, when we see Noah and the flood people omit the level of sinful and wicked degradation man had sunk to.
God in these times prolonged judgment because of His goodness. Had mankind repented, changed their minds, and changed their actions to align with new thinking and asked God for mercy do you think there would have been a flood?
God is a Good Father. If people actually read the Old Testament in its entirety they'd see God's wrath and anger is a drop in the bucket compared to His loving kindness and mercy. True God isn't some "Hippy" who winks at sin and rejects any values and says whatever feels good do it. Sin is destructive. Doing your own thing, that is satisfying your selfish whims and lusts at any moment, is not profitable. God gave us values and standards of living because He loves us and wants us to live abundantly blessed not in the misery of poor choices.