Hell is certainly confounding. As a boy who attended Catholic school until he was 14, I had this stuff drilled into my head. Catholic guilt, of course, is the result. Though I'm much more sober of thought and freed of these doctrinal bondages, the lessons and their implications still echo. Satan as a metaphor for the effects of bad, immoral decision making works. As a literal entity in a literal place called Hell, it raises all sorts of uncomfortable questions, like you did.

Whither a man gets his moral compass if not religion? Of course, you don't need to believe in God to be a good person, but without some divine deity to serve as "goal posts" if you will, we can see by a casual glance around this country and others throughout history who were corrupted by propaganda and disinformation, that humans by and large are one of the dumbest big-brain animals on the planet. I think we deserve the devil, metaphorical or not, at least some do. Doubtless this was a conclusion reached by religious leaders of the past for crowd control.