I'm not saying all dark or violent content is a bad thing by nature, but it's like: sometimes, why is it a thought that needs to be shared?
People derive enjoyment from different things.
For some people, excessive violence and gore is entertaining. Hence why slashers and horror exist as a genre.
Personally, I have a thing for B-Movies, which are often violent to such extremes that they become parodies of violent films. With the idea being that these films are so cheesy and awful that it amuses people.
Humans have had macabre interests for thousands of years. Be it things like gladiatorial combat in ancient Rome, to public executions as a form of entertainment (Among other things, human history is rife with things like human sacrifice and torture showing that there's some deep rooted hunger for violence within the species)
For other people, it's less about the violence itself and more about the worldbuilding it provides.
Much like Gabe Newell's old statement about "When someone shoots a wall, they expect a bullet hole" this directly leads to things like "When you hit someone with a giant axe, you expect them to be chopped by it". Add in the natural violent nature of society (Especially in fantasy settings and more notably, video games which are predominantly focused on violence for gameplay) and you get scenarios that lead into violence - Especially if you want to depict someone/a group as being "Evil" you make them do shockingly violent things to make people react negatively to them.
