The presupposition of this question that is often thrown at Christians by the skeptics is that people are innocent, that they are not deserving of any punishment.
However, as apologist Tony Costa has pointed out, this framework of thinking shows a lack of understanding of how God views sin. If people truly look into their hearts, they will see that we are really not perfect at all, that we have been guilty of the most treasonous acts and hideous crimes of the world.
"There are only two kinds of people in the end: those who say to God, "Thy will be done," and those to whom God says, in the end, "Thy will be done." All that are in Hell, choose it. Without that self-choice there could be no Hell. No soul that seriously and constantly desires joy will ever miss it. Those who seek find. Those who knock it is opened." - C.S. Lewis The Great Divorce
In the case of hell, there is this idea that innocent people are sent there. That's not the case. These are the people who hate God. These are the people who do not want to leave hell.
Hell is the place for people who do not want to be in the presence of God. They do not wish to be in a relationship with God and thus rejecting the gospel.
That is why God will give them up to their desires.
Therefore it is a just judgment by God on those who do not wish to be in His presence.