Come on, man. Challenging the methodology by which people draw inferences from a data set is like half of science. Just because none of this is important (and no, D&D character preferences are not important) doesn't mean the same basic tools can't be used.
We're never going to get a clear picture, but taking a pie chart at face value with no digging into the data is simply not something I'm equipped to do. It doesn't ascribe any incompetence to the people who make the charts to ask if there are confounding factors in play with the data.