It's formulated for production layers like leghorns, and it's the bare minimum. Companies aren't going to reformulate for smaller populations of chicken keepers.
Minimum protein requirement for laying hens is actually14%. Most current feeds are expressly made to appeal to backyard chicken people. So the companies assume we all have leghorns & sexlinks? I don't discount that sometimes extra protein is beneficial or that you shouldn't feed too much calcium nonlayers, but the feed companies don't produce feed that doesn't work for the majority of people. Amino acids are actually more important than protein. Freaking people out about using layer is getting old.