The form problem is his use of red and green colors, which I have called Christmas Camouflage because some color blind people will see both as olive drab, as shown above in the Vischeck Deuteranope Simulation view at the right.
The content problem is a change of scale between the results for zero books and heavy readers (more than 11 books). For zero books the left bar represents 8%, while for heavy readers the right bar with the same height represents 28%. Also, the left chart runs downward from zero while the right chart runs upward from a different origin. For heavy readers the left bar (for 42%) should be 1.5 times the height for 28% but instead is 2.5 times that height. An honest chart with the same scale and origin reveals that there still is a higher percentage of heavy readers (28%) than non-readers (23%) and it looks like this:
Does the 1990 Gallup Poll tell us nothing? No, it tells us something useful - that the percentages were changing from those the measured in 1978, and so the difference for 2014 is not from Pew and Gallup just phrasing their questions differently. Here is another honest chart including that data: