I agree, for the most part. I am really dismayed that so many video game developers pander to the lowest common denominator by making video games that are basically mass shooting simulators. In a few hours of Call of Duty you can literally simulate killing more people by your own hand than died in the entire two month long Battle of Falluja. But, you can see the same trend in Hollywood blockbusters and they rarely face as much scrutiny.
Does it desensitize people to violence? Quite possibly. Does it desensitize people to violence more than growing up in an actual urban warzone, like Detroit or the flatlands of Oakland? Absolutely not! People laughed at midnight basketball, but it probably did a lot more to fight violence than the ESRB.