This conversation is putting me in the position of devil’s advocate with alarming frequency. Having said that, several responses come to mind.
First is the eternal nature of hell. When my daughter misbehaves, I’ll put her in timeout for a few minutes. That way she learns not to do it again. But if I put her in timeout forever, what does she learn? Technically, I guess she does learn a hell of a lesson (so to speak), but she doesn’t have a chance to apply that lesson.
Second is the perception that hell is overpunishment. This makes sense to me, too. If hell is a place of punishment, created by a just god, then we can expect the punishment to relate to the crime. Being burned forever for one unrepented sin… I can totally understand people scratching their heads about that.
That’s why it’s so important to understand the church’s real teaching on hell. Hell is the state of
deliberate, willful separation from God. No one goes to hell accidentally. We know that through God’s mercy, even the hardest heart can come to repent. That’s all it takes!
Sometimes it’s hard, in this life. We’re all operating on finite information, filtered through human senses. We don’t always understand why we should be called to repent for some things. I wish I could dig up the passage in Faustina’s (I think) writings, of a dialog between Jesus and a dying man. Bottom line – there’s no reason to think God is going to damn anyone without giving them all the information they need to make the right choice.
If, given all that information, they choose separation from Him…

What more can be done?