The problem is, Facebook doesn’t show people content that they want to see. They show people content that they will engage with. That’s a very important distinction.
HN algorithm/moderators actually explicitly do the opposite: if a thread gets too many comments too quickly, it’s ranked downward. The assumption is too many comments too quickly indicates a flamewar and the HN moderators want to keep a civil discussion. The approach Facebook takes is to “foster active discussion” which on the Internet typically means a flamewar. Noting generates engagement like controversial political views. So that’s what Facebook’s algorithm/moderators show to their users.
Facebook absolutely is a social conditioning tool, it’s designed from the ground up to show people content that stirs their emotions enough to click “like” or the mad face icon or even leave a comment and wait around until someone replies back.