Firstly: My intention in this thread is in no way to put down religion, belief in God, religious people, etc. I ask that anyone who responds does so with respect to the belief systems of others, whatever they may be.
Being human, the only perspective I have is mine (as a human). I know that "our ways are not God's ways" or vice versa, which means humans often don't understand why certain things happen when they seem to be bad, hurtful, damaging, etc. Christianity teaches that things that happen to us that seem wrong, bad, unjust, hurtful, heinous, etc happen because there's a bigger picture and only God can see it.
Thinking in human terms from a human perspective and more specifically as a parent, I think of the following scenario:
Assume a parent loves their child dearly. That parent has a goal of raising a child who is autonomous (ie free will) and that parent knows that the child will learn from their mistakes. That parent shouldn't shield the child from every possible misstep and instead needs to allow the child to fail.
However...would a loving human parent sit by as they watch their child make a choice, go in a certain direction in life, etc that would be so dangerous that the choice would be lethal for example? That would never happen. A parent would never watch their child walk towards and step off a cliff for example, knowing full well the child will die and not say anything and watch it happen in order to preserve the child's autonomy, free will, etc. Also, if a child was persistent in wanting to walk toward the cliff, every parent would physically stop the child and literally prevent them from falling to their death.
Eternal hell is certainly the quintessential example of all examples of a fate worse than death, worse that stepping off a cliff, etc. God allows, preserves, protects our autonomy, our free will to the point of watching people step off the cliff to eternal damnation should they choose rather than stopping them. God knows what eternal life is really like. God knows what eternal damnation is really like for people; God knows the severity of it (a severity like nothing else).
If God's inaction was compared to the analogy of a human parent and child, God's inaction would be considered unconscionable. Why doesn't God step in in such instances?