I am a Christian and I can answer the question unto why God would create a soul that he knows will end up in hell. Let me first give you a disclaimer to say that I do not speak for all Christians, in fact, I am a very small minority in my current church that believes in predestination. However, I believe the answer to why God would create a soul that he knows will go to hell is in the Romans 9:14 - 23
14 What shall we say then? Is there injustice on God's part? By no means! 15 For he says to Moses, “I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.” 16 So then it depends not on human will or exertion,[b] but on God, who has mercy. 17 For the Scripture says to Pharaoh, “For this very purpose I have raised you up, that I might show my power in you, and that my name might be proclaimed in all the earth.” 18 So then he has mercy on whomever he wills, and he hardens whomever he wills.

19 You will say to me then, “Why does he still find fault? For who can resist his will?” 20 But who are you, O man, to answer back to God? Will what is molded say to its molder, “Why have you made me like this?” 21 Has the potter no right over the clay, to make out of the same lump one vessel for honorable use and another for dishonorable use? 22 What if God, desiring to show his wrath and to make known his power, has endured with much patience vessels of wrath prepared for destruction, 23 in order to make known the riches of his glory for vessels of mercy, which he has prepared beforehand for glory

So I believe what Paul is saying here is that you can't know how great it is to get an A unless there are also people getting F's. You don't know how great it is to be free of pain unless you've been in pain. And you can't truly worship and appreciate God's grace unless you know there was an alternative.