Being an obese slug on a high fat diet leads to Type II diabetes, not having the ability to ingest and process milk products. Drinking milk as a non-child is a beneficial trait in a population, being an obese slug on a high fat diet is not......but you've gotta be edumacated enough to know that a trait is a negative in population genetics ONLY IF it lowers your genetic fitness...your ability to pass on your genes to offspring. AND you gotta see that this benefit was larger in the long-ago past when diets were sometimes limited. If you could drink milk without getting sick, you had better nutrition, were stronger, and were more likely to pass on your genes for a longer period....it increased you genetic fitness slightly. NOW, we can do without milk as NOW we have knowledge about better nutrition, advanced medicine, and supplements, if needed.
Type II diabetes does not generally lower genetic fitness because it usually hits an obese slug on a high fat diet AFTER they pass their genes on......AND Type II diabetes based on nutrition and activity level is generally a new disease....as we are a lazier, fatter, and high fat diet population than we used to be.
.....but you're sooooo wicked-smaht you knew that before you tried to make milk the Devil.
I love it when a Creationist website, in an attempt to poke at the Theory of Evolution, starts talking about inheritable and beneficial DNA mutations.
Mr. nonsense man, Type II diabetes is the result of the distruction of the endocrine system by biofilm bacteria. This has been proven in practice beyond any doubt.
The mainstream medi-liars make tons of cash prescribing feckless poison to type II diabetics, so they are attempting to sweep the facts under the carpet in order to maintain that lucrative avenue of deception. (just as they do with most other diseases)
The fact that you choose to align with deception says much about your character.