He acknowledges what the Bible says in verses like
For God was pleased to have all his fullness dwell in him (Christ), and through him to reconcile to himself all things, whether things on earth or things in heaven, by making peace through his blood, shed on the cross.and genuinely hopes this really might happen
[Colossians 1 : 19-20 NIV]
For God had allowed us to know the secret of his plan, and it is this: he purposes in his sovereign will that all human history shall be consummated in Christ, that everything that exists in Heaven or earth shall find its perfection and fulfilment in him. [Ephesians 1: 9 - 10 Phillips]
For as in Adam all die, so in Christ all will be made alive.
[1 Corinthians 15 : 22 NIV]
For God has bound everyone over to disobedience so that he may have mercy on them all. [Romans 11 : 32 NIV]
just can't believe people like Hitler will ever accept God's offer of salvation.
There are three major problems here.
First: Salvation is not a Gift.
God's salvation does not depend on people's acceptance of it.
God doesn't offer salvation as a gift to be accepted or rejected. He has already graciously given it through the death and resurrection of His Son Jesus Christ.
It's a done deal.
God was in Christ personally reconciling the world to himself—not counting their sins against them—and has commissioned us with the message of reconciliation. [2 Cor 5 : 19 Phillips]A bit like someone putting a million dollars in your bank account rather than offering the money in cash for you to accept or not. It's in your account - it's already in the bank - it's a done deal.
Let me share a real-life illustration of this happening in 2018.
A couple from our church dined at a local High Street Italian restaurant. After finishing their meal, the husband went to pay the bill. The waitress told him there was no need as the bill had already been paid.
He contested this, saying he still had a debt to pay. Then the waitress explained that a local High Street trader has a table selected for each sitting and that he always covers the bill from that table.
So my friend and his wife had no debt to pay - it had already been taken care of before they had even eaten, and no matter how much the bill might have come to.
That's how it is with our sins. They have already been paid for - 2000 years ago. We have no debt to pay, our salvation was secured on the cross of Calvary centuries ago. It was all God's doing, we had nothing to do with it - it's a done deal.
Second: Jesus' Sacrifice Was Successful
Either Jesus was successful in His sacrifice on the cross for the sins of the world, or He wasn't.
All Christians I have met, including my friend, will agree that Jesus' mission to die for the sins of the world was successful. But then, illogically, assert that all will not be saved because some will not choose to accept God's gracious gift, thus contradicting their initial assessment of Jesus' success.
He (Jesus) himself is the sacrifice that atones for our sins—and not only our sins but the sins of all the world. [1 John 2 : 2 NLT]
And when I (Jesus) am lifted up from the earth, I will draw everyone to myself. [John 12 : 32 NLT]Third: God is Sovereign and Will Always Get His Way
Although God has chosen to save all, skeptics believe many (most) people will choose not to be saved and therefore overrule God's choice. In other words, the created being will overrule the Creator and His plans for His creation.
But who are you, my friend, to talk back to God? A clay pot does not ask the man who made it, "Why did you make me like this?"
After all, the man who makes the pots has the right to use the clay as he wishes, and to make two pots from the same lump of clay, one for special occasions and the other for ordinary use. [Romans 9 : 20 - 21 GNB]
People may plan all kinds of things, but the Lord's will is going to be done. [Proverbs 19 : 21 GNB]Believing salvation is a done deal, Jesus' sacrifice was completely successful and God's sovereignty will make sure His plan for the full reconciliation of His creation is achieved is the correct Biblical view and gives God the honour and respect He deserves.
God works out everything in conformity with the purpose of his will.
[Ephesians 1 : 11 BV]