|Laziness personified - on a box.|
These are very important things. The second point, a.k.a. "b" addresses the whole A.D.D. issue. Because people have the attention span roughly equal to that of a sand gnat, okay? And they can't be troubled with having to search for their information for more than a split second before something shiny or noisy or a picture of a celebrity comes around. So the information has to be right on the front of the box for everyone to see RIGHT AWAY.
The other reason that the nutrition needs to be brightly colored on the front of the box is because we as a society have become seriously, dangerously lazy. Combine that with our obsession with counting calories and intake (because that is easier than actually getting up and running around) and it leads to little emblems on the front of our cereal boxes. We want to know how bad out Honey Nut Cheerios are for us, be we aren't willing to take the extra time and effort required to look around the box to find that big, boring, black and white square. So it has to be on the front or we would never know unless we accidentally have a box that falls down on the floor on its side or something.