The very simple answer is pride. All humans have pride, honest pride, and vain pride.
It is the vain pride that calls us to sin, just as Adam and Eve did.
Why does a child not listen when their parents tell them not to touch the hot stove? Pride.
Why do people say things like “I’ll show you!”? Pride.
Why do people not obey God? Pride.
Nobody said it was logical. Just as, why don’t people trust God, a perfect being? It happens every minute of everyday.
Of course, God chastises the sinner. How else will the sinner reform his life?
People struggle with sin every moment of the day. It is part of our fallen nature, and our imperfection.
Fortunately, we have recourse to God and His mercy when we do fall, and His grace to help us battle sin, as well as strengthen us.
If one has "pride" and "struggle" with sin then they do NOT have "free will". Any sin is death. And they are slaves to that pride. They practice sin as John explains. They are to be prayed for that God will release them from their bondage. Their sinful behavior is understandable. They are in bondage to their sin. The Son must set unbelievers free from that bondage.
Believers, on the other hand, have been set free and no longer practice sin. We have become slaves to righteousness. We have a choice-to do God's will or to do our will. To do God's will is to walk His path. To do our will is sin. And we have no excuse why we do not live a perfect life except to say that we willfully, from time to time, lapse into our sinful and rebellious nature. We pray that God will reveal our sin to us and assist us in overcoming our sinful behavior so that we may walk with Him. But like Jonah, God WILL bring us around so that we will do His good works-to the praise of His name.
Of course, God chastises the sinner.
No, God chastise (disciplines) believers.