It's not about media, it's about traffic period. It's regulatory capture and subsequent collusion by Korean ISPs. Prohibitively expensive to run a streaming service like that even if you have local datacenters to reduce international transit fees (because you still have to connect to the local ISPs who will still charge you). https://carnegieendowment.org/2021/08/17/afterword-korea-s-challenge-to-standard-internet-interconnection-model-pub-85166