Why not platform-specific moderation? All social media content is available for consumption by a set of platforms the user authorizes. Those platforms are free to filter or moderate the content as they see fit. While not explicitly spelled out in TFA, this seems like the trivially obvious implementation.
We have platform specific moderation, in conjunction with high switching costs. If the content and connections themselves are owned by the platform then you have high switching costs. If the content and connections are instead owned by the user and all platforms share a compatible protocol for exchanging content/connections data, then the switching cost vanishes because there is no switching.
