This is like asking why people get so upset about being slandered and unfairly condemned. Sin is disobedience to God’s protective laws. He wants people to reap the benefits of obeying him rather than falling for Satan’s soul-destroying lies.
Sin is also an insult to the Lord’s holiness. His desire is that we should be free of self-centeredness and pride. Sin, on the other hand, is our middle finger response to all the magnanimous good God seeks for us. Like a child who demands his own way, humanity fell into the trap of sin in Eden when Eve fell for the idea that God was keeping back good things from her and Adam. Since then, the sin virus has infected us all.
Sin likewise helps Satan to drag many gullible people down with him to hell. We think we need to make our lives livable rather than trusting in the wisdom and loving protection of our Lord. Satan, a rebellious angel who dragged a third of the heavenly host down with him, doesn’t love us at all. We’re just pawns he can use, abuse, and toss in the garbage when we no longer are useful to his diabolical purpose.
God also showed his magnanimous love for us by substituting his son in our place to atone for sin. He could have just wiped out humanity or made us all robots but we wouldn’t genuinely love him. Neither would we appreciate his grandiose gift of salvation had he not allowed us to know both good and evil.
You Think You’re Going to Heaven is my next book, provided that something doesn’t happen to stop me writing it. People need to think about eternity and realize that life is so easily snuffed out. Like an elevator, we can only go up to God or down to eternal conscious torment. As much as we would try to deny this, it’s the way it is.