it's either about ruining the ethos, stealing the data and/or changing the protocol.
Honestly, it's probably all 3 and more we haven't even though of yet. I don't think anyone could have predicted all the scandals Facebook has been involved in regarding misuse of user data, and that was just on their own platform. ActivityPub literally hands them the keys to the castle. Add in all the toxic political stuff and.. it just makes my head hurt.
Anyway, I appreciate having the conversation with you. Discussing it has helped solidify my feelings about it.