I think you're reading that breakdown a bit wrong. It said human breast milk contains 4.2 grams of fat per 100 millileters. That is a little bit of a confusing read-out and hard to track in a percentage measurement, but it's not as much fat as you are reading it as. The issue is that it really throws you off due to the fact that the units are different, one measuring in a unit of weight and the other in a unit of volume. However, my gut says that you will probably find it's significantly less than the 4% you have in cow's milk.
You could also be correct that I was off about the near 0% thing. I'd just picked that up on hear-say from someone who in-turn said they'd heard it from a lactation specialist in the late 80s. (Just when they were starting to learn about why human breast milk is better than formula, contrary to the messaging of the previous era.)
But, yes, I am sticking to my guns on the point that it is irrelevant to adults. To infants, you definitely DO NOT want to give them cow's milk. That is supported by the wiki article as well. For adults though, it doesn't really matter. In fact, the article you linked stated cow's milk is richer in proteins and other nutrients. This would mean the cow's milk is actually better in that sense. It's only that a human infant does not possess the ability to digest all that stuff.
Percentage fat is usually measured w/v (which is grams per mL). This is true of cow's milk as much as the other forms of milk compared on that page.
If you read the
Fat content of milk Wikipedia article, whole milk is 3.25% fat by weight.
If you read the nutritional lab on a carton of whole milk:
8 grams / 240 mL * 100 = 3.33% fat
In comparison, human milk contains:
Human milk contains 0.8% to 0.9% protein, 4.5% fat, 7.1% carbohydrates, and 0.2% ash (minerals).
[40] Carbohydrates are mainly
lactose; several lactose-based oligosaccharides have been identified as minor components. The fat fraction contains specific
triglycerides of
palmitic and
oleic acid (O-P-O triglycerides), and also lipids with trans bonds (see:
trans fat). The lipids are
vaccenic acid, and
Conjugated linoleic acid (CLA) accounting for up to 6% of the human milk fat.
[41][42]
In either case, the dietary value of certain milks is not what people talk about when people switch away cow's milk to organic or plant-based milks.
Many people in general worry about antibiotics, hormones, and pesticides that make it into cow's milk. All medications that a human (or animal) consumes ultimately enters the breastmilk, as well as many growth hormones that are naturally part of the animal. There are certain cow hormones that can stimulate human growth. For instance, accidentally consuming the thyroid gland of a cow (or beef contaminated with the cow's thyroid gland) can cause hyperthyroidism. This is actually a medical phenomenon known as
recurrent hamburger thyrotoxicosis.
Human milk also contains high concentrations of a unique form of carbohydrate called
Human milk oligosaccharides (HMOs). They are the third most abundant component of human milk after lactose and fat. Other forms of milk do not have this. Research have suggested that HMOs are not digested by the infant, and it instead supports the intestinal microbiome. Human milk may be better for supporting a healthy population of commensal bacteria (a probiotic, essentially).