The depravity of man can be seen in the crucifixion of Jesus. If God is love, and Jesus is God, then it was Love incarnate that was nailed to the cross. Jesus acted only in love - and abided by the highest moral standard there is - God's. He only did what the he saw the Father doing (John 5:19, 14:10). The reasons of those who did not follow Jesus then are no different from those offered today.

Thus it seems that the natural consequence of love in a fallen world is pain and death. It is further counter-intuitive to love - which essentially makes one vulnerable. As a result, we do not love fully.