When someone says, give them what they deserve, I understand those feelings. I would ask; what if we got what we deserved? Isn't that the reason Jesus hung on the cross, to become the penalty for what we deserved?
I can honestly say that in my life, all that I did against God and so many others, if there was anyone who deserved to burn in hell for eternity, it is me. No one will ever convince me that the love, mercy and grace of God, didn't apply the shed blood of Christ to my sins to purchase my undeserved forgiveness. No, I cannot judge anyone for their sins, no matter how evil they may be.
The whole reason we are here is to offer the same opportunity for forgiveness that was poured out to us by Jesus when He cried out... IT IS FINISHED (it is complete)!