A: Your question rightly emphasizes that it was people who killed Jesus, not God, and that is correct. It was not the purpose of God that Jesus should die such a terrible death on the cross. Part of Jesus' mission on earth was to live and die as a mortal of the realm, but the manner of his death was not mandated by God as an atonement for man's sinfulness. Jesus did not have to die in such a cruel manner as a result of God's will.
To understand why Jesus was killed, we have to understand the political and religious climate of that day and time. Jesus was a good Jewish boy, raised in the Jewish religion, and taught the laws and dogma of his family's religion. But Jewishness was really more than a religion—it was a way of life that dominated the lives of its followers with ritual and obedience to the authority of the priests and other officials. As Jesus grew into an understanding of his real mission on earth, he could no longer continue to blindly follow the rules. His was a mission of proclaiming a new and better way of knowing God—a way of originality and freedom—the freedom of the religion of personal spiritual experience. He challenged the scribes, the Pharisees and the Sadducess and their authority, and threatened to upset this rigid way of life. Jesus loved the Jewish people—his father Joseph's people—and many of them loved him in return, but those in power did not love Jesus.
His final temple discourse spells out his love for the Jewish people, and his condemnation of those who would deny them spiritual freedom.
And right after that, the leaders met and voted to impose the death sentence on Jesus
They were wicked men, motivated by fear of losing their authority over the people and they were determined to put a stop to Jesus' growing popularity among these same people.
Nonetheless, Jesus death was a supreme expression of his willingness to follow God's will even to the end of his life, whatever it was. While it was not God will that he be murdered, it WAS god's will that he die as a mortal, as all mortals do. In Jesus' case, his death turned out to be terrible, but the important thing to remember is that he did fulfill his mission by willingly submitting to this humiliating death.
Also, by being subjected to death in the same manner as all human beings and then returning, Jesus demonstrated for all time that death is not the end--that, like Jesus, our life continues on after we are laid to rest here.
Perhaps if Jesus had died a peaceful death people would have paid him little notice beyond the short span of his life, but by being killed in such a public and tragic manner and then to return in triumph gives joy and hope and peace to all believers.
In death through torture Jesus demonstrated for all time, to the awe of those surrounding him, his unfailing reliance upon the Father in heaven and his love and forgiveness for human beings, even his enemies.
There are many valuable lessons that we can learn from the cross of Jesus, and you can read about them HERE and HERE
Thank you for this question—so appropriate now that we are heading into Holy Week and Easter. I hope that this reply has been helpful to you."