A friend of mine learning English misused "peoples". While I was able to explain to her how to use "person", "people" and "peoples" (I decided not to mention "persons"), I realised that I didn't have a clue why English uses the "person" and "people" the way it does.
Ok, first check whether ELU had already answered the "why" aspect. Nope, nothing. Google? No luck either.
Ask a question? Not so fast. If I don't provide a link to a dictionary, then I'm going to get closed as being available in a "commonly-available reference". Ok, link to the OED entries about "people" and "person", and show how they don't mention the relationship with each other. I should be ok now, right?
No. My question about why English uses "person" and "people" got marked as a duplicate of questions about when to use "person" and "people", and got dupehammered.
Next time, to force the person closing it to use primarily opinion-based instead (which doesn't attract the dupehammer) ("The precise reason why we do this is probably unanswerable"), should I pre-empt claims of being a duplicate by linking to an existing ELU question and spelling out in words of one syllable how it is not a duplicate?