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.
They already do this though, it's called Facebook, Twitter, Instagram, etc. That's why the EEE argument doesn't make sense. The distinguishing features people keep talking about already exisit in a wall garden yet Mastodon has users. The features that Mastodon users want is freedom and control. Threads can't compete with that but Threads can introduce millions of users to the concept of federation.