I'm sorry, does having genes that explicitly help in drinking milk beyond infancy not count? Not just one gene mind you, several genes, some of while evolved multiple times in different areas. How does that mean "we're not mean to drink milk after infancy"?

We domesticated grains and legumes around the same time, does this mean bread is bad for us? Are potatoes slowly killing everyone? Is chocolate evil? We're generalists and have a long history of scavenging, we're designed to eat whatever we can get including grass, dirt, and carrion. Our immune system and digestive system are both quite good at processing rotting meat compared to most mammals, and we're much more resistant to toxins too. Dogs are also generalists, yet we regularly eat large amounts of things that will kill them, like onions, garlic, and grapes. We enjoy the taste of natural pest control like mustard and capsaicin. Milk is a rare nutrient dense and safe food compared to what we were usually eating before agriculture.