I also tried after hearing people on HN speak so highly of their recommendation system.. I only watched (in full length)/searched for/liked videos of a specific gender/race/age group.. yet even after liking over a hundred videos, then 100% of the videos they suggested to me were the wrong gender/race/age group. YouTube on the other hand is capable of recommending the correct videos after watching just a couple.
It’s very easy to conduct this experiment, just make sure that the race you target doesn’t represent the majority of the users in your proximity. For instance, if you’re in Norway then try to get TikTok to recommend Asian girls aged 20-35.. sounds like it should be easy, right?