I feel like this is coming from a naive socially illiterate nerd stereotype. They are smart people, they might as well know much more than you expect.
The whole point of TFA is that pure intelligence (particularly "computational thinking" type of intelligence) is no substitute for the knowledge and methodology already explored by various humanities and social science fields.
If so, why didn't they make such predictions in 2012 during Facebook's IPO?
This is such a false dichotomy. There exists many, many technical programs that go to field and do that type of "social" research, using the precisely the same methodologies, knowledge of which end up with UX designers, product designers, product managers etc. This TFA readily admits. In other words, anything that social sciences can offer is already being incorporated into those programs. (I am talking about likes of human computer interaction, user experience, information processing science, network science, and tons of other hybrid programs)