YouTube recently banned accounts and censored videos that contradicted the WHO - the same WHO that said you shouldn't wear masks during the pandemic.
Centralized systems are censorship accidents waiting to happen. It's super bad already, and we're still in peacetime. Imagine how shitty things are going to be if that changes and the nations that can exercise ultimate control these vast centralized systems feel that free communication via them poses an existential threat due to crisis.
Then there's the whole Instagram "no nudity" thing. Even outside of times of crisis, the de facto photo sharing default has excluded an entire category of human art and creativity. No single organization should have this much dictatorial control over our society's ability to express its own culture, nevermind its ability to permanently read (and share, and mine) your private conversations.
Build around centralized systems by running things yourself. Run your own mailing lists so your groups can communicate outside of algorithmically reorganized timelines designed to benefit advertisers. Self-host Discourse (forum) or Mattermost (web chat) or Gitea (git web). Make local backups of your servers and vpses data partitions so that you can fire them back up somewhere else when the time comes.
Your community will thank you in the long run, and you will be contributing to making all of society more resilient and more expressive/free.