Here’s some simple, quick advice, which I’m sure that anybody that’s moderated any kind of online group will agree with.
If you see this notification come up in your Facebook group:
Ignore it. Just ignore it and move on. Do not activate this feature.
No idea how this got through Facebook’s development flow, but this seems like a path to immediate confusion, angst, and endless problems for most communities.
If you need admins, choose them from members that you know and trust.