Well, for all those human beings whose lives on Earth were a constant torment, thanks to the greed and immorality of their fellow humans, maybe that idea gave them the strength to go on, and to endure it. Would you have preferred that they just give up and be obliterated?
All the more reason to persevere if there's no guarantee of a reward in the afterlife. Is what we are and do here on Earth meaningful? Certain believers seem to suggest there's no meaning to this life if there's no afterlife, but I submit that the opposite is actually true.
And it's odd to claim that the only reason people suffer on Earth is through 'the greed and immorality of their fellow humans.' Did humans create typhoons, trypanosomes, birth defects, retroviruses, or earthquakes? Could it be that you're depending on the Good Lord to make good in Heaven after his rather indifferent treatment of us all down below?
We adopt the ideas that tend to justify our innate inclinations, not the other way round.
Can't dispute that. But some ideas we adopt are more self-serving than others. I'd love to think that we'll all have a ball in the great beyond, and the evil will get their come-uppance. But since I don't expect either, I'm less complacent about justice in the here and now.