Because there are very worthwhile texts to read that improve ones knowledge about oneself and humanity and the universe, which in turn allows oneself to make better decisions and have a better mindset.

Reading fiction still helps a little with that, but is mostly "just" entertainment, which of course is also worthwhile.

When I was young I only read fiction, but as I got older I realized reality is incredibly complex and disturbing and found non-fiction far more interesting. So much of the past remains relevant today and there are no shortage of times real people have not only imagined but also implemented ways to exploit each other and their environments, for good and for bad, often in ways that do come across as utterly crazy, so it is hardly a boring category. These days I would rather make sense of the world I am in than some fictional universe. I do like British humor though.

Aside from the accurate list you posted, I felt similarities as well with hitchhiker's guide to the galaxy.