"Simple" has more than one definition.
Simple can be uncomplicated. Simple can be elegant.
This particular simple is unsophisticated. If it weren't for the vocabulary, I'd put it in the Forrest Gump category of simple.
Or maybe it's only intended to look simple and homespun, the better to excuse its ignorance and ridiculous prejudices. I am especially insulted by his depiction of women as somehow too soft for the hard world of democracy, which is as odious as it is inaccurate.