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Here's how I see it breaking down:
It's unethical to hold people liable for not knowing things they have no reason to know.
Therefore, an ethical god would not send such a person to hell for being ignorant of god's sin/salvation program.
Also, if a person is not convinced a thing is true it would be because no one has presented a convincing case for it, which wouldn't be his fault. In which case the responsibility lies with others, and he shouldn't be held responsible for their failure.
Therefore, an ethical god wouldn't send such a person to hell for being unconvinced of his sin/salvation program.
So, the only people in true jeopardy of being sent to hell are those who buy into the sin/salvation program but don't measure up.
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