@FediPact i think the reason they chose AP is just, atproto basically requires the whole application stack to be designed around it (and i feel like they wanted to compete against bsky not with it anyways) while AP can mostly be treated as an automatic post import/export protocol that doesn't prescribe any specific architecture requirements that'd interfere with what they were actually tasked with making
and activitypub is already mainstream enough to have an image of legitimacy, (where making a new protocol is both technically hard and would require them to actually try to make it sound legit)
so i honestly think we just happened to be the convenient protocol for facebook to be able to take and say "look we're decentralised too don't look at bsky look at us", we were just convenient for marketing and the federation that's there is just what's left now that the stunt is over
like i honestly don't think it really was some evil plan to EEE us (if that really was the plan federation would've been there at launch and it would've actually worked, but i think what facebook was truly after was those looking for an exit from twitter, not those who were already here, they didn't actually care about us, they wanted to distract those leaving twitter from the shiny new kid on the block called bsky, and saying "we'll also give access to that other place that you found was too confusing when you first tried to leave twitter" was just a way to make their offer sound more appealing to those who'd otherwise be signing onto the waiting list for bsky)
and i honestly feel like there were a few good meaning engineers in threads who thought they could do a good thing by getting threads into a federated playground despite the evil overlords, though as it's shown they've largely been left to the wayside by now
