So should we let everything be legal?
Since we disagree?
That is not true freedom.
Of course not. Murder should be illegal, as should theft, rape, assault, and lots of other real crimes in which victims are objectively harmed. There are an ample number of real crimes and real criminals to keep our law enforcement agencies and our justice system fully occupied.
Speech and other forms of expression (written words, movies, video games, etc.) are not criminal, no matter how hateful or offensive or stupid or ridiculous or shocking or immoral some people may find them. You may find some of that expression to be unpleasant and objectionable, but you are just going to have to learn to tolerate it if you are going to live in a free society rather than a regimented dictatorship or theocracy.
Unless it causes direct, tangible harm to others (e.g., the famous dictum about not yelling fire in a crowded theater, because the resulting panic and stampede could result in injury and death), all such expression is protected by the First Amendment.
When I was in high school, I played "Wolfenstein 3D" - the first of the first-person shooter games that hit the market. I've also played DOOM and Duke Nukem. I also enjoy naval simulations like Harpoon 3 for the PC (where I can knock off more folks in an INSTANT using tactical nukes than I could playing Wolf 3D for hours) and Harpoon miniatures.
Let me add that I turn into a pile of mush in the presence of guinea pigs, kittens, and (to a lesser extent) puppies. I feel safe from charges of being a total softie due to a taste for veal parmesan.
I consider myself well-adjusted, DESPITE playing the violent video games as a teenager.
We got problems in America. Violent video games are NOT one of them.