According to https://wiki.php.net/phpng, they benchmarked against Wordpress 3.6 (the current version is 3.9). I couldn't find anything about the Drupal benchmark, but it could be a simple "Hello world" for all we know.
Drupal's big two issues are bootstrapping drupal, because all those module hooks stack up quick, and the sometimes large amount of queries run to generate a page. Drupal 8 has gotten better about not loading half of the world when a blog post is loaded, but 7 is just a wall of functions.
I really don't understand people's aversion to database tables. I have a join, the world is ending! Pay attention to your indexes and 9 times out of 10 everything will be fine. For that 1 other time, there's Varnish.