Why does everyone swear so much in The Witcher 3?

Gotta wonder how many people are down voting because they think the title is moralizing, when it's anything but that.

There's nothing like going for a nice long walk around the world of The Witcher 3 and meeting some of the locals there. They say the nicest things. "Sod off, you misborn clod," a guard will tell me. "Got so fucked up once, blood came out me ears," a chap at the docks will announce. Or if I'm really lucky, "Go fuck your mums tits!" What a world to live in.

The thing is, I love this about the game. Being scolded by the ruddy-faced inhabitants of The Witcher 3 has long been one of my favourite things, ever since I first played it eight years ago.