The problem I see with Threads isn't what Meta will do with fediverse data, it's the power they have with owning 97% of the entire fediverse network [1].

Embrace, Extend, Extinguish. Owning the vast majority of the fediverse userbase will cause them to have a large amount of power to compel users or servers to do whatever they want. What do you do when Facebook implements a new feature and all of your followers complain that your using a Mastodon server instead of joining Threads that has this feature they want? You either go against your entire community or let Meta takeover your account.

As such, the resolution is to not let anyone have this much power. It being Meta makes it easier to hate on them, but no single server should own the vast majority of the network, let alone (100M / (100M + 2M + 1M)) = 97% of it [1].

[1] Threads has 100M users and is rising fast, Mastodon was recently stated to have 2M active users, the rest of the fediverse can be estimated to be, say, 1M. As such, Threads has about 97% of the userbase.