How to argue against this claim

[Mystic]

Hi All,

So Obviously the Bible and god ways are full of evil deeds, and EVIL agenda
Slaves, murders and much more

Some Religious person would say,
Yeah but think of a child that sees a doctor cutting a man legs to save his life.
So like us the child lack of understanding the big picture.

Please give smart way to explain this comparison

Thanks

Think of a child that sees a crook claiming to be a doctor to steal candy from children.

So like the the religious person the child lacks understanding of the big picture.

This made me lol so bad.