There is apparently a rule of capitalization that I never learned. The rule is that after a colon (":"), the initial letter of the item should be capitalized if and only if that item could stand as itself as an independent clause.
- Here is an example: This is a sentence.
- Here is another example: just an isolated item.
The rule is clear enough, but I swear I never was taught this in any class, from middle school English all the way through college composition, and certainly not in any linguistics class, which, contrary to popular understanding, has nothing to do with such prescriptivist poppycock.
Anyway, although I believe these types of rules to be merely "prescriptivist poppycock," I nevertheless work hard to understand them and even enforce them with my students, because I am teaching them to write English mostly with the intent to get good scores on exams written by people who worship unerringly at the altar of prescriptivism. "Know your audience."
I enjoyed this humorous example of the rule, below (credit to linguistics blogger Geoffrey Pullum, writing at Chronicle of Higher Education's Linguafranca blog).
- There’s one species we can keep in the lab without the animal rights activists getting upset: fruit flies.
- Something wonderful happens when you attach a banana to a drone: Fruit flies.
[daily log: walking, 7km]
I had never heard of that rule either: neither in elementary school, nor while earning a doctoral degree, nor anywhere in between. I like your description of it as prescriptivist poppycock: Sounds like B.S. to me.