Why are so many video games so dark?

To be more specific, all hack and slash games are very dark in appearance, as well as, in my opinion at least, games like skyrim and oblivion. Is it just because they are all basically games about fighting? I really don't understand. If they want to give it a rough and manly feel, they can do it without making it so absurdly dark and black filling in every crack and crevice. Is there a reason for this? Devil may cry and Dark Souls, left for dead, Dynasty Warriors, Bayonetta. I'd be more inclined to play Bayonetta were it not so dark. It's pretty stupid to say, but the atmosphere just makes me feel bad when playing a game that dark for too long? -shrug-

even the new game of hyrule warriors seems very dark. E3 they showed the bright meadows and then they got blasted down and the trailer was well lit but the actual game play, everything was dark again! Ugh. I don't know.