I agree: with this title, the author neatly sidesteps the problem of having to define 'intelligence' and ending up in an endless debate about whether his reason

I agree: with this title, the author neatly sidesteps the problem of having to define 'intelligence' and ending up in an endless debate about whether his reasons indeed pertain to 'intelligence'. 'Not intelligent enough' can probably be dissected into another 20 points, each portraying a characteristic that is a necessary, but not a sufficient, part of 'intelligence'. You are both right :)