Its interesting that everyone focuses on the privacy and the EEE risk of this, but my reasons for leaving Facebook were that Facebook is actively-allowing-the-promotion-of-genocide-because-not-moderating-is-better-for-their-bottom-line Evil. I left facebook because I'm not willing to provide the (even infinitesimal) boost to their network effects that my account had. For the same reason, Threads is an instant defederate on launch.