Part of the problem would appear to be what it means to be in the state of grace.
Sin, first of all, is a choice.
You choose something (an act, or a failure to act where you have a moral duty to do so) as opposed to choosing God. To choose God is to choose to do as He wishes us to (and that is largely but not absolutely defined by the Ten Commandments).
If you make a specific choice to violate one of the commandments, you are choosing self (your wants, desires, wishes, choices) over God.
Another way of saying it is that you reject God.
So if you die while being in a state of rejecting God, God will honor your choice. We talk about God condemning you but the reality of it is that you condemn yourself; you reject God.
To be in a state of grace is to be in relationship with God. To sin is to reject that relationship.
If you are still rejecting that relationship at the point of death, God so honors your person, your choice, your free will, that He accepts your choice and you continue on in the next life in a permanent state of rejecting God. That in its distilled essence is what Hell is about - the permanent separation from God.
That is a somewhat simplistic answer, but it cuts through all the chatter, the obfuscations we can come up with and puts it in as plain a language as I can.
We sometimes get caught up in a world where phrases and words get thrown around without any real understanding of the underlying meaning of them. Life is not a game; it is for real and for keeps. We can get ourselves caught up in pseudo sophisticated arguments, and forget what we are arguing about is reality, not some word game.
God doesn’t play “Gotcha!”. He gives us real choices, and we make real choices with real consequences - some good, and some horrible. Assuming one is of the age of reason, one is responsible for the choices one makes. One can say “I really didn’t meant it” - but guess what? God is not one’s mother or one’s father or whoever it is one says that to, and whom one can fairly consistently B.S. God sees our innermost being. We may lie to ourselves that “we didn’t really mean it” - but we made the choice.
If we honor our relationship with God; if we choose God’s will over our own will, God will honor that.
And just so, if we reject God and choose our own will, God will honor that.