There are a few problems with the facts in the bodybuilding.com perspective you listed, TaoistWarrior. I'll list the most glaring first.
The enzymes necessary to break down and digest milk are renin and lactase. They are all but gone by the age of three in most humans.
Note the use of the word "most". If your biological ancestors consumed large quantities of lactose-bearing foods, the chances are good you are not lactose-intolerant. For instance, most northern Europeans have plenty of lactase enzyme as adults, as do many other ethnicities with a history of cattle herding. However, most Asians lose the ability to process lactose as adults, as do most Africans. So the word "most" in this sentence means "approximately 60%". In other words, around 3 billion people on this planet have no problem at all digesting lactose quickly & efficiently, with few to none of the symptoms listed in the perspective. You'll know if you don't produce lactase; go drink a tall glass of skim milk (skim has much more lactose than whole-fat milk). If within 3-6 hours you experience intestinal discomfort and/or smelly farts, you are lactose-intolerant. If you aren't lactose-intolerant, the above point doesn't apply.
Those with a casein allergy -- the major milk protein after whey -- tend to
die when given foods with casein in them. You'll know if you have a casein allergy because your doctor had you go buy an epipen to save your life if you accidentally eat some.
All that said, many people have a milk
intolerance -- that is, they experience intestinal and cellular inflammation in response to dairy consumption -- without necessarily an
allergy which can still cause other problems. Abstinence from wheat (gluten) and dairy (casein) is often the first step toward better health in the obese. In many cases, abstinence from gluten alone restores the damage done by gluten so that dairy is again well-tolerated in someone who has the ability to produce lactase as an adult.
For the second point, yes, casein is slower to digest than whey. I would scarcely typify it as something the body struggles to get rid of, but it is a slower-digesting protein.
Unfortunately some of this gooey substance [coagulated casein, according to the author] hardens and adheres to the lining of the intestines and prevents the absorption of nutrients into the body.
Sorry, this point is total bullshit. Theories about stuff "hardening" and "adhering" to the inside of the intestine have absolutely zero scientific support except in the case of the few people with severe intestinal dysfunction (that usually kills them in short order). This reads like an advertisement for the colonic industry. That's a discussion for another day, but suffice to say that "mucoid fecal plaque" is a term invented and exclusively used by the colonic industry to describe
a condition that does not exist. Pure myth to drive sales of colon-cleansing products.
The most serious difficulty with milk consumption is the formation of mucus in the system. This mucus coats the mucous membranes and also seriously affects absorption.
Yet more bullshit. In healthy, non-allergic individuals, milk does not promote the formation of additional mucous in your system; this has been repeatedly studied and debunked. It's a very popular myth, though, since the viscosity of milk and mucous are similar enough that people complain of "mucous formation" after drinking milk. There is certainly a hypochondriac effect, however. If you believe milk creates mucous and drink milk anyway, you'll complain about more coughs and sneezes, but you won't produce a statistically significant amount of mucous more than the guy next to you drinking no milk at all.
So, to sum up, the perspective offers only a single valid point: casein protein digests more slowly than whey isolate, and by adding casein via your milk, you are slowing down digestion of a product for which you paid top dollar for fast digestion. The rest of the perspective is either total bullshit or an exercise in weasel-wording to make a point.
That said, the sole valid point is still a good point for a post-workout shake. I'll be drinking my protein shake with water rather than my Hood's Calorie Countdown; although Calorie Countdown has no lactose, it has plenty of casein, and if I wanted casein protein I'd have bought that instead!
Regards,
Matt B.