Is milk really good for our health? An evolutionary arugment on the opposite.

Lactose persistence is one the well document example of selective sweep in human evolution. People who have the mutation to digest milk as adult tend to have more offspring, and lead to population expansion.  If we believe this scenario, then it would suggest that milk-consumption should lead to health problem in late life. In other words, early advantage should be paid by health cost later, a typical trade-off phenomenon during evolution.

To elaborate this even further, this is similar to steroid usage in some way. Steroid usage will boost performance in young adult, but this performance advantage will be paid in late life.

This is of course is just a logical reasoning from my perspective or speculation in many other's view.