I think the point of the people who wants realism is this:
In the past, games were harder, were in fact 'Nintendo Hard'. If you beat one of those games, you have all the rights to brag about it online, in real life, everywhere. You still have these bragging rights for old school Nintendo games.
Nowadays, games are far easier, with elastic AI (think NFS Underground) and if they are hard enough then people complain and never play again (as it happened with Sniper Elite).
However, people still brag about beating these easy games. So, I conjecture that what the 'realistic' party wants is a game where you have to earn your bragging rights.
So far there are very good examples of this. iRacing is a racing game/service where if you are number one you totally deserve at least to test drive the real thing. And you need a lot of hours dedicated to the game to be able to achieve this. Bragging rights totally deserved.
I think this Sniper Elite game also counts for that, in a far lesser scale. You have to aim higher at long range because the bullet travels downward, and it takes some time for it to reach the target. It's more difficult than snipers in other games, so if you get a really long distance kill you can post a video of it in youtube and receive kudos for it. Also: getting shot really hurts. You do everything you can to avoid getting shot, in fact you do everything you can to avoid been seen, there is no running towards the armed enemies trying to be a faster gun. This last point is what the article is about. Some dude beating the Batman game using Batman fists and getting shot in the face all the time.
In the end, I think this is why all games should have difficulty settings. In fact most of them do!
You play on easy if you want to escape reality for a while and relax.
You play on hard if you want 'realistic' bragging-rights-deserving gameplay.
Hey, this whole article is a non-issue.