From Burroughs' text: "The orange juice prepares the digestive system to properly digest and assimilate regular food. Drink it slowly. If there has been any digestive difficulty prior to or during the change over, extra water may be taken with the orange juice."
In essence, it gently kick starts digestion.
It also says that if you ate a raw diet prior to the cleanse, you can return to eating raw fruit and vegetables at lunch and dinner, respectively, on the third day of breaking. (First two days are oj.)
The soup is for those who ate the Standard American Diet (SAD) prior to the cleanse, and are easing their way into a raw diet. I assume that jumping right into that much fiber after the cleanse could be a bit shocking to your digestive system when it's not used to it.