It's not trying to make things readable; it's trying to make things look like there was more light in the room when they were shot. In rooms with high lighting, some objects have glare. That's "correct"—it's what would appear in the training data.
Wait, did it? Isn't the middle photo being shown for comparison only, rather than as an input?
EDIT: Finally got the paper to load via the helpful wayback machine link provided in another thread. It looks like the goal was to simulate a long exposure with a short exposure. So whitewashing of "bright" areas in the original might be expected.
You do realize that, in a camera sensor, light is the signal, right? So the more light, the higher the signal-to-noise ratio, which means that yes it does have more information available to extract.
And yes, I quite realize that the input is (a). I'm guessing that in your display you are not seeing that there is a brighter spot in the middle of (a) corresponding to the whitewashed area in (c). Try maxing out your brightness if you're on a phone or laptop and you should see it. I can even make out letter shapes in (a) within this bright spot.