Video games have pretty much always been violent. With rare exceptions like Pong, most video games involve one character beating down another. Even beloved children's favorite Mario is constantly under the threat of violent death, be it from barrel-hucking gorillas or hammer-hurling turtle-monsters, and he solves his problem by killing his tormentors, stoving in their skulls with the heels of his boot or hurling them from suspension bridges. Let's face it: violence is fun.
Good old-fashioned violence is especially prevalent in MMOs. How many fantasy MMOs do not include missions, at some point along their questing paths (and usually and especially early on), to go out and kill ten of something? Kill ten goblins and bring back their ears for a bounty! Kill fifteen orcs and bring back their heads as proof of your deed! Kill twenty bears and bring me back their pelts so I can make you this hat that you'll outgrow mere moments after receiving it! Bandits are attacking my farm, go kill all of them to send a message to other bandits that attacking farms is bad! Kill everything that lives in this dungeon so you can get that ring that is slightly better than the one you have now that adds a small bonus to one of your secondary stats! Kill all members of this one problematic species in this area, causing a local extinction event, for a title!
Frankly, MMOs tend to have the very worst kind of violence - the murderous acts committed by the player have no permanent negative consequences. The character goes out and kills a lot of stuff, loots the corpses, gets paid for it, and the mobs respawn. Not only are they rewarded for their violence, but nothing they killed actually stays dead and nothing around them really changes.
But it's not usually MMOs that come under attack when people are pointing their trembling, angry fingers at violent video games as the cause of misery and woe. Blame most often falls on shooter games, like the original DOOM, or sandbox games like Grand Theft Auto or pretty much anything by Bethesda. Those games depict violence in a much more realistic way than the cartoony, bloodless violence of most MMOs. But really, isn't that better?
I've recently gotten back into Fallout 3 and Fallout: New Vegas, which are unquestionably violent games. The violence in these games is very different from what I see in MMOs. It's WAY more gory, for starters - enemies explode in a spray of red, meaty chunks when you take the Better Criticals perk, but even without that perk there's still the chance of bloody dismemberment from a headshot or multiple shots to the same limb. And if you don't manage to gib your target with the kill shot, you can just shoot or smash the corpse until it explodes.
Unlike most MMOs, the bodies of your victims stick around for a while - presumably until Mojave scavengers drag them off somewhere to eat. If you kill a non-hostile NPC, people hear about it and you are vilified via the reputation system; most MMOs do not have killable NPCs walking around the open world, because if they did, jerks like me would run around killing all of them and there would be no quest-givers left for all the nice people.
If you try talking to a NPC in Fallout: New Vegas with your gun pointed in their face, they react differently than if you holster your weapon first. If you fire your gun in the middle of a crowded settlement, people will duck and run for cover. NPCs in MMOs are usually oblivious to violent player-character behavior, standing or strutting around completely indifferent to violent psychopaths swinging swords around in front of them. The point here is, violence in Fallout: New Vegas has long-term consequences. It's not the bloodless killing of MMOs - it's horrifying and grim.
It may sound like I am condemning violent video games, but I am not. Frankly, I'm glad this violence is there because, let's face it, the Grumpy Gamer needs an outlet for when he is frustrated (which is dismayingly often). Scoring a gory headshot in a video game is a way to vent antisocial, psychotic rage without hurting anyone, and it's less expensive than smashing things. It's more satisfying than punching a therapy pillow. It saves the world from frightening emo poetry or ranting manifesto blogs. I am not more inclined to commit violent crimes because I play violent video games; I am much less inclined to do so, because I've worked that demon out and have seen the gruesome consequences. I can pretend that that Powder Ganger collectively represents all the trolls and broken game mechanics and stupid lag spikes and all the other aggravations plaguing me, and I can blast his head into a spray of red gooey chunks with a well-placed Anti-Materiel Rifle shot, and laugh at the way his ragdoll body flops to the Mohave dust. Then I can do the same to all his buddies that come charging over to see what happened, inadvertently creating a handy little kill-zone for me. Then I can lob a bunch of looted dynamite at their heaped, mangled corpses and bomb them into a fine red mist, and scatter the remaining chunks across the Mojave with a mini-nuke, laughing maniacally all the while. And nobody gets hurt.
But that's hilarious over-the-top violence in a single-player game. MMO violence is a lot sneakier because it's so much less in-your-face. Any of my MMO characters have committed vastly more acts of violence than even my most bloodthirsty and thuggish Fallout character. The Lord of the Rings Online is a good example of that - on the surface, the game seems sweet and almost wholesome, but I figure it's the most violent video game I have ever played, bar none.
My Hobbit Hunter has slaughtered literally millions of orcs, goblins, bandits, wolves, bugs, trolls, giants and other things just for deeds or loot. When he needs to fashion some kinship uniform hats, he heads to a particular set of ruins in Bree-land and butchers 200-odd bears (and their cubs) for the hides. He will "farm" hundreds of one type of monster in one small area for an extra point of Agility and an incremental increase to some resists. Way back in the day, he completed the Orc-slayer deed in Lothlorien several times over - thousands of orcs culled from a handful of camps - because there was a tiny chance one of them would drop a level 59 or 60 Second Age weapon, and those were really valuable at the time. My Hobbit Hunter pulled out his crossbow and shot all those things to death. Millions of things. Enough to qualify as one of history's greatest war criminals, or some kind of natural disaster. But LotRO doesn't draw nearly the same kind of heat as a Fallout game might, because the kills are essentially "clean." No scattered bits of skull, no sprays of crimson arterial blood jetting from a neck-stump. The violence is far more casual and gratuitous, but not nearly as visual.
MMOs provide a different kind of outlet for the eternally-frustrated. Yes, you can go out and commit senseless acts of virtual slaughter, but there's also a community to connect to and communicate with. In a single-player game, you're the predatory lone wolf engaged in the grim task of cleaning things up and setting things right. In a MMO, the horrific violence is a social activity. Groups of players band together to murder all the monsters in a dungeon or to kill a powerful boss for loot. Okay, sure, the orcs in your MMO are clearly evil villains out to destroy the world and watch it burn... but so are the Raiders in the Fallout games. Raiders are the crank-snorting human version of orcs. Their cultures are roughly similar in terms of brutality and violence, they place almost no value on life, they wear the same spike-covered clothes and they decorate their settlements with human remains. The real difference is, where you may kill a few hundred raiders in a Fallout game, you drench yourself in the blood of thousands of orcs in a MMO. Except not really, because the orcs don't bleed.
A kind of ironic footnote here: The Lothlorien Orc-slayer deed that my Hunter completed several times over in a single-minded pursuit of Second Age loot rewards the character with an increase to the Innocence virtue.