This argument against God is as old as time itself. If God is love and evil exists, either God is weak or He is not as loving as we make Him out to be. It usually comes in a more philosophical form, but you get the idea.
The problem is that God has an eternal perspective (and we do not). The central message of the Bible is that our rebellion against God (sin) has eternal consequences that are so horrible that it is almost beyond belief. The very fact that God, Himself, came in the flesh to be tortured and killed in a painful death on the cross in order to save us should give us some indication of how serious the situation is.
God’s love compelled him to sacrifice Himself to save us from the results of our alliance with evil.