Two other hypotheses they don't seem to have ruled out: - Their site is so awful that 80% of people click back before the page finishes loading, thus appearing

Two other hypotheses they don't seem to have ruled out: - Their site is so awful that 80% of people click back before the page finishes loading, thus appearing to not have javascript - Their ad is so awful that almost no people click it and a few bots make up 80% because the total is so low.