I hate the fact that for a large number of people, this will be how they will be introduced to the fediverse and their view of it will be tainted by Meta. I also dread seeing Meta spam in my federated timeline. And I also fear Meta building its own proprietary features on top of the ActivityPub protocol, making the content generated with them incompatible with independent clients, and allowing Zuck to spread his monopoly to the fediverse as well.