I've been reading some of the forums at a lyrics site. There is one section called "Lyrics Explained" which is particularly upsetting. People ask for an explanation for every simple song out there. Its like they only think literally, or they can't make intellectual leaps. Its sickening.
Not knowing how to contextualize is often a problem, too. There's a song about the Donner Party that someone didn't understand, because they had never heard of it!
My mom is getting her Masters in Gifted and Talented education(or something comparable) and she told me that only 15% of the population(I think) have adult level ethics. If this is true it is more than possible that a majority of the population also has a hard time with abstraction, contextualization, metaphor and whatnot. They could be all around you. They could be reading this post.

Weird.