When you remove all the fillers and other toxins (water, alcohols, preservatives, perfumes, emulsifying wax, petroleum ingredients, etc.) and replace them with healthy, active, beneficial ingredients your skin is able to go about the work of healing itself.
Think about what happens when we remove processed food from our diet and replace it with healthy fruits, veggies, quality proteins, healthy fats, nuts, and seeds. We begin to feel better, sleep better, lose weight, our mood improves, etc. Thus, our body doesn't have to work as hard to clean out the yuck. Without all the distractions, your body is able to begin the work of healing itself of all the 'crap'.
The same is true for skin. When more than 2/3 of a product contains these "junk foods" for skin, your skin needs to take much of it's energy cleaning that junk out that there is little left for healing or repairing skin.