Is American society violent ?

The 23 years old Korean student killed 32 peopele and injured onother 35 peopel in Virginia Tech last week.
A lot of young people suffer from depression, have a variety of problems and don't talk about them , neither share with friends some difficulty that they have, not dealing with the problems by themselves.
In fact , American society is very violent. There are so many stores selling weapons and force equipmen. You can buy a gun everywhere, legally and illegaly.
I think the gun control is not very efficient and the government should work much more on it and not let people buy weapons easily like clothes!