Your philosophy about hell is plainly wrong. You are anchoring your reasons on the old testaments Gehenna and Sheol being translated as hell. You imply that when hell is mentioned in the bible its either grave or the dump site outside Jerusalem. And the fire as symbolic of cleansing. I would like you to consider this verse, Matthew 25:41 where all your erroneous reasons will be seen. The verse read : "Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire prepared for the devil and his angels: for i was a hungered and ye gave me no meat..." Here you must see that some people on the left hand of the Lord on the judgement day are cursed and are going to the place where the devil and his angels are destined. That is the hell, the place of eternal torment which the devil and his angels are going to and also the cursed people mentioned by the verse. Now, can you apply all your philosophy that hell is Gehenna or grave or that eternal fire is symbolic of cleansing and a tool for purification? Will there still be purification for the devil and his angels in the first place? NO MORE. Jesus said the devil is already condemned. Can they be put to a grave or dump in Gehenna? Impossible. They are spirit beings. And it is really true that God will throw some men to hell, those cursed, with the devil and his angels. But that is still to come. After that judgement day that God has appointed. God being benevolent, good is also a God of justice. Those who have not known God or His righteousness or the correct religion will not suffer by that fact but they will be judge according to their works and according to their conscience ( Romans 2:14-16).