Life should be banned too, because it does have a lot of that stuff as well and has a negative impact on people ;-)
But seriously, for kids it is kinda banned. That is what those rating systems are for. And adults would have their mature content filtering (Steam has such, Itch not so much). But once you are legally an adult, "the" gov should have no business telling people what they can or cannot view, play or create. The thing is, what is frowned upon is different for every country. It is arbitrary and even changes with time. The US for example is rather strict on nudity and profanity (swearing), while violence seems ok. In Europe it is the other way around.
And for games, like in: fictional stuff, the discussion would have an additional layer of abstraction. Yeah, some non-players regularily claim that eg playing ego shooters makes people violent. They got it backward. Violent people might be interested in such games, but that is the same as having an interest in sport cars and playing racing games. I do not like to drive a kart, just because I played mario kart.