Of course there are going to be some people who can't differentiate between fantasy and reality, but they are not going to need video games to influence their decisions. Those are the types of people who cross over the line between what is socially acceptable and what isn't all on their own.
Blaming entertainment media for crime or behaviour is a cop-out. It's utilizing a scapegoat in order to ignore a serious societal problem. Blaming pornography for the objectification of women is attacking a symptom not the deep-rooted societal antipathy towards them that allows pornography to exist. If we did not already believe women to be less then men that form of objectification wouldn't happen.
The same applies to video games and whatever they are being blamed for this week. In the case of high-speed car races the culture of worshiping a motor vehicle has existed since they became a mass consumer item. They were marketed from the get go as being essential to defining ones masculinity. There's a reason for the jokes about male sexual prowess and cars: the car companies in their need to ensure sales created that atmosphere.
Passing the buck to movies or video games allows us to feel morally superior about an incident without having to accept any responsibility. The truth of the matter is that as a society we are all guilty in the death of that cab driver last week. If we did not continue to worship at the altar of the internal combustion engine, praying for heightened status through our devotion, street races like the one that took his life would never happen.
To paraphrase the National Rifle Association: video games don't kill people - people kill people.