The backlash is "We don't know, and you dumbass without a degree are trying to figure this out without any formal training".

I welcome doctors, researchers, and people who know what they are doing to experiment with the human body. But when a computer science major armed with nothing but a few textbooks in body chemistry claims that he has "figured the body out", I am going to assume otherwise.

Does he have any cooking experience? What is his medical background?

Its not so much that "we don't know", but "the creator of Soylent clearly doesn't know", and yet he wants us to believe that he does.