Let me suggest something to you. Half Life 2 has the violence equivelant to... Mario.
What? I'm crazy? Well let's think about it. How would we describe the violence "Half Life 2?" Probably like "You shoot chainsaws at zombies and rip their torso in half!" Well, guess what? In Mario, you crush innocent, cutesy brown animals under your own body weight and laugh as numbers spew from what used to be their cranium.
That's an exaggeration. But this whole "violence in video games" concept, particularily when people say it reflects how violent people are in real life, is all exaggeration.
Sure, I know your argument. Graphics. There's no blood in Mario, and it's not NEARLY as realistic as HL2. But does that really change anything? Sure it's a more believable fake, but fake nonetheless. If you squash a goomba, you could dallop ketchup on you TV, and maybe squint a bit, and that would be just as violent, eh?
Violence in video games is really in our heads, and I think more people should understand that. Yeah, I know Mario is more kid-friendly XD But this is just a message to all those people who despise violent video games and make a buig fuss about it. Calm down, jeez.