Wait until everyone learns about bioavailability of nutrients with respect to type of food -- ie. Animal-based nutrition is more bioavailable than plant-based nutrients. [1]
I think it's important to consider the inputs. Carnivorism is just herbivorism with more overhead. Perhaps I do need to eat ~3 times the non-heme iron to get the same level of absorption, but plant crops usually win out over cattle when it comes to scalability.
Is plant iron more bioavailable to cattle animals than humans? That might tip things slightly in favor of carnivorism, however cattle does a lot more than just convert non-heme iron to heme iron and facilitating that excess resource usage may be more trouble than the heme iron is worth.
The iron and zinc from vegetarian diets are generally less bioavailable than from nonvegetarian diets because of reduced meat intake as well as the tendency to consume more phytic acid and other plant-based inhibitors of iron and zinc absorption. However, in Western countries with varied and abundant food supplies, it is not clear that this reduced bioavailability has any functional consequences. Although vegetarians tend to have lower iron stores than omnivores, they appear to have no greater incidence of iron deficiency anemia.
[1] - https://academic.oup.com/ajcn/article/78/3/633S/4690005#1098...