Car manufacturers aren’t required to document how to repair “infotainment centers” because they aren’t critical to the operation of a car. Making them more useful might require a car manufacturer to spend more money by allowing more requirements to be imposed upon them.
I thought this was obvious: avocado seeds are large because they were eaten by giant sloths. It would surely be much more difficult for an avocado tree to reproduce without the involvement of an animal, and giant sloths are not around anymore, so at some point humans must have taken over from the giant sloths, so there was probably some place where humans and giant sloths lived at the same time.