Gregory's Server@gamingonlinux The issue I see with auto-signups to the biggest instance isn't with decentralization directly, but with the moderation issues that instance has been having since long before now.
I've heard of several instances taking the nuclear option of defederating M.S due to harassment of their users and the lack of moderating them on M.S's behalf. If their moderation was lacking then, encouraging rapid growth of their population won't improve it.