Bookmarked:

This is both a seemingly bold thesis and a surprisingly accurate description of what appears to be going on in large parts of the internet:
Because the audience online so wildly over-samples 12-year-olds relative to the population, and because all social platforms work like highly competitive marketplaces, you are constantly being disciplined into creating content that is essentially, though not explicitly, for 12-year-olds.
From my observation, this not only applies to content – which the article is talking about – but to design on the internet at large: the attention span and constant hunger of teenagers seems to drive a lot of the design decisions that trade depth and complexity for the easily consumable “fast carbs” …and the lowest-possible threshold for the sacred cow of “engagement”.