I believe "double predestination" is a misnomer. If by "double predestination" you mean does God take steps to purposely and actively send people to hell, then no; I would agree. There is no evidence of that in scripture.
But if God just simply sat back, did nothing, and let us had our way, we would all go to hell, right? Wouldn't you agree? I would hope you would as a Catholic. With no spark of God for man to co-operate with, where would man go? Man by our very nature is sentence to hell aready; every single one of us.
What people have done is completely did away with the concept of man going to hell. Instead, man is in some sort of limbo on earth where he gets to choose where he would like to go, either heaven or hell. Under this concept God shines His light to reveal Himself to varying degrees and people make their choice. Of course, if you lived in some foreign country and never heard the gospel, then God will treat you differently. And people are at a lost as to explain why someone who, understanding the issue, would choose to go to hell. Nevertheless, people simply don't believe in the concept of hell or how we can be so wicked that God would send us there.
The truth is that man is going to hell. God, in His grace and mercy, intervenes to save some of us. The question is why He doesn't save all of us?
By ‘double predestination’, we describe the theology that people are either destined to heaven or hell and that’s where they go period. The Reformed seem to step very lightly around this idea.
We believe that God doesn’t simply sit back and do nothing for any man. The idea of limbo here on earth is a strange concept that I haven’t heard of before.
We are instructed to bring the Gospels of Jesus Christ to the world. It’s our mission. What God does with those who haven’t heard is beyond our understanding. We don’t know. Same as unbaptized children. We don’t know.
All we know is what we’re instructed by Jesus.