I dont think that on the whole the average American is more violent than anyone else, the problem lies in that there are so many of you, thats why your crime figures are higher. I dont know how easy it is to get a fierarm in the US but I do know that even with our extreemly strict gun controlls over here (UK) it is not that hard to find a gun if you really want to.
You can manipulate figures to say more or less what you want them to it's all a matter of presentation.
As for US films and TV been violent have you ever seen the Martial arts films out of HK? or the Japaneese Anime, it is what society asks for the industry delivers, it's got to be bigger and better each time.
As a very non American I personaly dont feel threatend by Americans for the most part I find that they are rather nice folks, with the obvious exceptions, NYR fans and all those who dont think that a certain Mr Rose should be forgiven:-)
going into hiding yet again LoL