The best description I’ve heard of hell is that it is simply separation from God. When you are made for God, that is the torture.
Why would God permit this if he loves us? Because those who know have made the choice to deliberately live by our own rules and not God’s. Essentially it is a version of Satan’s ‘I will not serve!’.
Flip the question; if you are of the opinion that God is wrong, and that some sin ( fornication, murder, whatever) is just fine, even when God is very clear that it is against his natural law… and you died confirmed in this belief, why would you want to be in full communion with God in a very radical way when you die? God isn’t putting the screws to you because he’s angry you disagree, he’s respecting your choice to disagree with him and separate yourself from him!
What would you have him do? Know you have chosen to completely disagree with this fundamental point of natural law, but over-ride your will and your choice and have you come into communion with Him where you will have no choice but to be overwhelmed by the Divine Presence?
What you’re asking is to be co God with God; and that isn’t possible.
Now, there is all kinds of nuance there. People live in a fallen world, and many suffer through irresistable ignorance. To sin gravely, you have to have grave matter, full knowledge of the sinner, and full consent of the will.
Some people who struggle with purity lack one or two of those. (It’s grave matter because of what it is, but if they don’t have full knowledge, or full consent of the will, it may not be mortal). A man who grew up in a household of poor catechesis and secular gospel of sexual license may have seriously compromised ability to have full knowledge or give full consent.
So why enlighten them?
Because like a person who may think that smoking is fine, they are incorrect. And we want the fullness of truth for them.