Why does anyone?
Reddit mods, Fediverse maintainers, corporate social media. This whole "curate and censor" bamboozle is antithetical to the internet I grew up on. The most upsetting part is that so many folks today are happy about this status quo and delight in the fact that their opposition gets canceled or de-platformed. All it takes is one political pendulum swing for the cheerleaders to become the oppressed.
Social media needs to be P2P. Not centralized, not federated, and not controlled.
End users should have complete autonomy over who they follow, who they (de-)boost, and how their filter/attention algorithm works.
Users should have the capability to share their { follow, block, boost, mute } lists with others, but it should be optional and not something mandated from the top by a third party.