Fantasy books are shaped and formed by violence.
Mind you, this isn't universal - there are always laudable exceptions, gentler stories with their own devoted readers. But the mainstream of fantasy, the ones most prominently on display in the bookshops, and the ones that new fantasy readers often come to first, are the books about wars, warriors, bloodshed either official or informal or both, the slaughter of other people or strange monsters, and the overcoming or at least endurance of other peoples' violence.
Forgive me, Not-So-Gentle Reader, for putting words into your mouth, but you will say to me: Fantasy worlds are violent, rough. That's how things are in places like that. You have to do what you can to survive.
Which is, in the strictest sense of the phrase, begging the question. Who made them that way? Why, Ungentle Reader, you did, and all your kind.
Personally, I blame J.R.R. Tolkien for starting it off, with his split personality and unconscious racism. He hated war, as it was fought in his time - the barbarism, the atrocity, the senseless deaths. But he looked back, in a very Christian manner, to the olden days when real heroes had shining swords and the lakes of blood they waded through didn't matter, because their cause was just, and they were only fighting infidels - none of these messy complications that the World Wars introduced, about impersonal deaths and people like you on the other side too.
The Lord of the Rings is all about the way the glory of war and the extremes of good and evil have passed out of the world, to be replaced by progress and the simple beauty of village life. It's an incredibly sad story. It's also all about violence, and the way it affects ordinary people.
Now, I suppose this is an entirely legitimate topic for discussion, but how did it become so central to the entire genre? It's almost impossible to imagine someone living in a fantasy world who doesn't own or acquire a sword. Most fantasy worlds have a war of some sort, or the threat of war, going on somewhere - if it's not a war, it will be an incursion of monsters, a plague of brigands, and so on.
Partly, I suppose, it's because having a sword makes problems appear so much simpler, and weapons equate not only to power, but to a convenient hand-sized chunk of power that you can just pick up and use.
Tolkien, mind you, wasn't anywhere near alone in his world-view - the same ideas about chivalry appear in the work of ER Eddison (The Worm Ourobouros), Andrew Lang (the Blue Fairy Book &c), CS Lewis (Narnia), and GK Chesterton (no fantasy per se, but The Napoleon of Notting Hill is a perfect exemplar of the idea).
It's interesting how all the swords end up in the hands of upper-class men - even Lucy got a bow, traditionally a yeoman's weapon, and Peter and Edmund were given swords straight off the mark.
I think that it's a very Victorian thing, as well as a Christian one - the current age is unlike any other, they said, and Mankind has never had it so good. All previous ages (and, by analogy, fantastic worlds) were barbaric and violent in comparison.