I think Netflix might be categorized as "other media" further down, where it says "social media platforms rank by predicted engagement ... ranking by popularity

I think Netflix might be categorized as "other media" further down, where it says "social media platforms rank by predicted engagement ... ranking by popularity is common for other media", so the negative quality correlation might not apply. Quality being negatively correlated with engagement sounds like social media version of people preferring junk food over gourmet.