The explanation includes the following statements:
Animal-free dairy is made without animal inputs. The non-animal whey protein is identical to what’s in cow's milk, but made without using a single animal in the process. Animal-free dairy is vegan (as are all the other ingredients we use in our products!).
Non-animal whey protein is the same whey you’d find in cow’s milk, except zero cows are involved. How?! The bovine whey protein gene (stay with us) was digitized in an open source database (like an e-book!). Microflora are given the blueprint of the gene sequence, and then fermented in a tank along with some plant sugars (it’s just like brewing beer!).
The product, though, is marked as OU-D.
Another statement was
Brave Robot does not contain any animal inputs, but does contain milk protein. It’s a paradox! The FDA requires a declaration of milk proteins because the animal-free whey protein is molecularly identical to whey protein that comes from cows. We encourage ice cream eaters who have a milk protein allergy to use the same precautions with Brave Robot that they would take with dairy. (But, reminder - Brave Robot is gloriously lactose free!)
I wrote to the company asking for the reason that they would be listed as Dairy under the laws of kashrut (whether it was an issue of machinery or allergens or something else) and this was the response:
OU-D indicates that the product is dairy, contains a dairy ingredient, dairy derivative, or has been on dairy equipment. The non-animal whey protein we use is identical to real dairy – our certification team designated a “D” in “OU-D” to reduce any confusion about the nature of the product and its ingredients. Our ice cream is real dairy!
That explanation did little to clarify -- if the whey protein is identical, digitized and grown in a plant, then why would it, even as identical in structure, be halachically dairy?
Is something milchig because it is identical to what is milchig on even a chemical level?