OpenStars, 7 days ago

Hexbear essentially predated federation iirc, then migrated to Lemmy when that became possible. Hexbear is I think roughly the 3rd oldest instance - sorting its posts by Old shows that it is 4 years old, while lemmygrad.ml is 5 years old, and lemmy.ml is 6 years old. Lemmy.ca in Canada and the Finnish sopuli are both also 4 years old, mander.xyz is 3 years old, but Lemmy.world, by far the largest instance with ~80% of all users, is only ~2 years old, being formed at the time of the Rexodus.

Read some more about it here (don't click the link there to follow further - in true hexbear trolling fashion it will simply take you to a picture showing a pig in the act of pooping, you have been warned) and especially here, e.g.:

Two of the sites listed there, Hexbear (aka. chapo.chat) and Bakchodi, do not federate. They are not part of the Fediverse, but they are using Lemmy. Hexbear is actually running their own fork of Lemmy.

TLDR: bc they felt like it, then they didn't, now it seems like they almost do again, bc facts are nearly always stranger than fiction:-).