This site has done an amazing job of turning learning a language into a game...Duolingo
Having people categorize themselves on an objective technical skill such as math is at least slightly more reliable than having people self judge on such a subjective skill as writing.
Many people I went to college with were certain their one act plays could win awards and that their sonnets would outlive them. I certainly wouldn't trust many of them when it comes to something as nuanced as the American legal system.
A better breakdown of the populace would have been to separate out people based on the level of education achieved, or perhaps by specific college degree, or even split out people with legal backgrounds from the average layperson. This would remove all the "touchy, feely" issues his current survey has.
With that said, this Tennessee man may be a danger to society, and his actions really creep me out, but I don't believe that he broke the law as it is currently written.
For what it is worth, on his poll I would have fit this profile
Writing skills > Math Skills