It’s not about highly specific knowledge: none of these questions are justifiable for a graduate level program, they are better served as prompts for essays that Americans write in their college applications. With these questions you are not going to be engaging with anything particularly deep, but you may produce something that sounds deep. But sounding deep and having actual depth are very different things, and the latter can often look very boring or painstaking, whereas the former always appears profound—and it seems like all of these questions are meant to help the student produce something “profound,” not necessarily something thoughtful or difficult.
I think the prompts being "easy" in this way is sort of the point. An applicant can demonstrate their mastery of language and the topics they select, producing an essay that goes far beyond the obvious leading direction (which most of the questions have).
The examiners are, I imagine, quite good at the close reading of essays which this sort of question produces. That ought to address your second point.
All Souls College doesn't have any students, graduate or otherwise. It's primarily a place where people can conduct research into any topic, most often in the humanities.
It frequently hosts journalists, politicians, lawyers, etc, who have had successful careers outside of academia and who may have no academic qualifications other than an undergraduate degree, and sometimes no degree at all.