I still feel that the distinction is not so clear.

Why is "banning lead" seen as a biological "change", but "banning soda" is tagged as a "social effort"?

I re-read it and I get a feeling that what it's talking about is not so much "biological" vs "social" but rather.. "physiological" vs "psychological", and arguing that psychology can be a lot more complex to deal with than physiology. Which I guess is fair.