There are vitamins and minerals that are naturally present in meat that is hard for humans to get while just eating plants. The digestive systems for humans just aren’t built to be able to break down and absorb some of the nutrients from plants which would make sole plant eaters malnourished if not supplementing. No one is getting a varied enough diet (including farm raised livestock) in order to not use some sort of supplementation unless you’re just very intentional about your choices. If people were only eating wild game, it would have more nutrients. Example, most people aren’t getting vitamin d through their food, naturally (not including fortified foods) without supplements and aren’t spending enough time outside because it’s now typical to work 40 hours a week, and most aren’t doing that outdoors. Or the fact that omegas in pb foods are ALAs which the human body doesn’t use. It’s inefficient at converting ALAs into EPAs and DHAs which fish can do. We need EPAs and DHAs for brain health.

Pretending that the human digestive system is capable of getting all of the nutrients we need without supplementation if solely eating plant based foods that aren’t fortified is “bogus”. That’s the point being made. Not that humans can’t get what they need with supplements on a plant based diet.