milk is naturally a mixture of whey (fast digesting) and casein (slow digesting). To create cottage cheese, the whey is skimmed off leaving only the casein behind. It does not have to do with the fat content. Casein won’t be listed as an ingredient.
After making cheese (any kind, including cottage), whey milk gets left behind as a byproduct.
So we end up with a whey-free product (cheese).
PS: There are of course a few cheese-making processes that don’t include removing all the whey from the end-product, but usually most types of cheese are whey-free.