The reason Keith's explanation is not universally accepted is because it is incorrect.
Unfortunately, the idea keeps perpetuating because people like Keith keep peddling it.
Bernoulli states that there is a relationship between speed and pressure. In this instance, it is the pressure change that causes the speed change, not vice versa.
The air does not know it has a longer path to take, and it does not speed up because of it. The air speeds up because the wing moving through the air causes an area of lower pressure above the wing, and an area of higher pressure below.
The pressure regions above and below the wing are caused by the fact that the gas molecules in air have inertia.
Bernoulli cannot answer your question, so whoever wrote your question doesn't understand why a wing generates lift either.