Factual error: When they are eating, there's a box of chicken labelled PFK (Poulet Frit a la Kentucky), the French equivalent of KFC. This film takes place in the USA, but was filmed in Canada where most products are labelled in English and French.
Factual error: When the survivors are first in the mall, you can see a store called Roots with a Canadian beaver logo. While the movie was filmed in Canada, it is supposed to take place in the USA where Roots has a different logo. (00:17:05)
Answer: It was actually explained in both versions that the zombies went to the mall because it was a place of familiarity, a place that they could remember even if they didn't know why.
Tobin OReilly