That's not a very good headline. Of course they did it for food, the model was about whether they could have domesticated themselves fast enough without being forced.
I'll have to actually look into the research; I have trouble imagining how one would model that in silico.
I read about this just recently. It was more of an evolutionary cousin thing; dogs and wolves diverged like a million years ago, well before we were in the picture. The ones humans ran into on our way out of Africa would have been from a different subspecies, and potentially were prone to domestication from the start, while the one that became modern wolves were confined to (now submerged) Beringia until the end of the ice age.