The problem is that they are not compensating for how your eye perceives things. Your eye+brain will adjust light sensitivity locally based on what you are looking at in real life and hence it will never be that dark. If you just throw global illumination on something in graphics either the light areas will be too bright or the dark areas too dark compared to how you it would look to you in reality. You need to adjust things much more than what they have done to get it right.
Just one more aspect of this game hinting how unoptimized it is (and unfinished). I believe they have basically just turned global illumination on and gone home (slight exaggeration but I think you understand what I mean).
That makes sense.
Actually real life is dark when in building shadows with the sun to the opposite side... you can see it when you left a place more without sun light to outside... that is when your eyes start to make the environment more clear until it becomes very light.
You can see that when you take photos... they usually get darker than what you see after your eyes adapt to the light.
Same when you are in a beach with white sand... you take a picture and it looks too shinning like what you see when you enter in that area but after some time your eyes start to see it more "normal" or "less shinning" and become different from the picture.
Dark room too... if you take a picture it is everything dark and you can't see nothing in the picture (without flash of course lol) but when you are there after some minutes your eyes adapt and start to see everything.
That makes me think I should compare more with what a picture looks and not how I see with my adapted eyes