You are right: God the Father is Love and love does not destroy what it loves. 

Who said God the Father was the cause of anyone's death?  Sin is the cause of death, not God.  Sin is it's own punishment.  There are consequences to sin based solely on the nature of sin.   God allows us to face those consequences--because it would be unloving not to.  There has to be negative fallout when we sin--so that we will stop doing it.  One of the consequences to a capital crime is that we risk the death penalty.  

When someone is put to physical death, they are not destroyed.  It is their earthly life that is brought to an end.  They still exist, sir--unless you are going to tell me you don't believe in an afterlife.  If someone goes to Hell, it is not God who puts them there, but they who have created their own Hell through the poor choices they made in their earthly life.  

Liberals make the mistake of thinking that "God is love, therefore there are no consequences to our poor choices."