I believe that we just borrow our lives from God. And He is the only one who have right to take them away from us.
At first I didn't agree with having death penalty. But when you watch the news and see all those fucked up things people do without remorse, most likely you would want them dead too, especially if you're connected to the victims.
You are absolutely right. Only when one of your loved ones get killed or raped by these monsters, you will understand their pain. Till then, you will argue for forgiveness and all that BS. I am all in favor of the death penalty, and I don't care what the others think about it.