Well - and you'll have to take my word for it that this is not personal - most of my acquaintance with graduates prior to my own degree was with scientists, rather than humanities, people, including teachers (my dad taught).
The general consensus amongst those did, it is true, tend to be that subjects like history were somewhat unique in that you could get on quite a long way in the subject by just regurgitating facts that you learned parrot-fashion. But take it from me that in many other subjects that simply isn't the case: they would be looking for originality, insight, and thought. The idea, say, of a physics graduate being able to "basically parrot fashion what your lecturers say" and get a good degree like a 2:1 is, frankly, laughable.
And it has crossed my mind, as I try to navigate through your flaws in elementary logic, that perhaps you're a case in point for your argument that one doesn't need to be intelligent to get a degree.
Perhaps it does just depend on the subject.
(and, before I upset any historians out there, I'm not saying that there aren't any insightful, original, intelligent and/or thoughtful history graduates!)