Perhaps you would share that article with us??? Doesn't make much sense to me either. An egg had ~6-7 grams of fat and ~6-7 grams of protein, no fiber, and is a great leavening and binding agent. A high quality free-range egg is around 1/3 saturated, 1/3 monounsaturated and 1/3 polyunsaturated fat.
Flax is almost all fat and fiber, almost no protein, no good for leavening, possibly good for binding IF ground up to a very fine meal, has no saturated fat and not much monounsaturated fat. They also have very different vitamin and mineral profiles....so I'm not sure in what way 2 TBSP flax plus 1 TBSP of water is the same as one egg?????