My black friend said black people can't drink milk. What's wrong with milk?

Some of these comments... It's not that we cannot drink milk, it's the lactose (sugar enzyme) that makes milk hard to digest for some of us. We are not a monolith because we have different diets depending on where we are from.

Milk is drank in some African countries, but it's mainly goats milk I believe which is similar to human breast milk. At least that's what I've read.