Well… Hades really isn't the "Satan".

To be honest, in Greek mythology, Hades was probably the straightest arrow you could find.

Not to mention, it's easier to relate to the bad guy who shows his flaws and embraces what he does, versus the "holier than thou" God-like entity.

Thank you. Some one else that has read into Greek myths and knows that Hades is the least assholic of the Greek Pantheon. But you know 'MERICA has to deem an entity related to the dead as EVIL so that uneducated audiences are not educated any further.
/rant