The arguments I've heard about tracking etc are misguided and don't understand the actual risks.
Firstly, posts on the fediverse are already likely being consumed by advertising platforms like Facebook & Google. It would be trivial for big tech companies to setup relays that act as scrapers.
Secondly, the value in platform's tracking individuals is for advertising. There is no mechanism for these platforms to identify you browsing the we if your instance federated with threads. Your instance won't share cookie sessions etc with threads. It doesn't increase your exposure.
Thirdly, these platforms have the know how to deal with spam and they will be incentivised to share that tech with other federated instances.
Don't get me wrong, Facebook is an evil company. But I haven't heard a decent argument as to why them joining the fediverse is a bad thing. We always have the option to defederate in the future.
Change my mind.
But they obviously don't have consumers' best interests and rights at heart or even care about them for that matter, which they've demonstrated time and time again
They are anything but benign and I don't think anything good can come from their involvement
Just the fact that they will bring so many users to the fediverse through their own locked down platform is a problem in itsself, bad intent or not because it destroys the decentralisation if there are millions of users all on one instance belonging to one company
Facebook is evil. But the fediverse should be resilient to evil bad actors, no matter who they are.