The rewards for evil behavior in computer games should generally be material, and potentially quite lucrative, with hidden pitfalls along the way (the townsfolk rising up against you, for example, or losing the trust of a key character), but also the possibility of completely getting away with it all.
The rewards for good behavior should mostly be the satisfaction of being forthright and upstanding, with minimal material gain. Materially, this is hard mode, which is a bit of an issue because most RPGs deeply emphasize the importance of equipment. There may be hidden benefits along the way (for example, gaining an important office because your honorable behavior has been noticed by someone/something important), but there's still the possibility of simply ending up a doormat with little to show for it.
Even the above is far too simplistic and a poor reflection of reality, but I too agree with the general consensus: In the context of games, you're mostly rewarded for being good, and heavily punished for being evil. It's kind of the opposite of the above: Your reward for being evil is the satisfaction of acting like an asshole, while your reward for being good is... everything else.
Which amounts to the developers treating you like a lab rat, essentially. In reality, a complete piece of shit can get all of the money, all of the bitches, all of the guns, all of the mercenaries, all of the space in the history books, accomplish the mission, fuck your mother, and kill your dog, and there ain't shit anyone's gonna do about it. Many such cases throughout human history.