Because some of them don’t see the danger of Threads. And I’m not only talking about the EEE tactic: I’m also talking about the festering sludge that will grow on Threads and that you have also seen. For the Fediverse, it will be a moderation nightmare. And be sure that Zucc won’t even moderate his platform; he doesn’t want to and, as far as he’s concerned, it’s even out of his range.
Think about it this way: if a user starts spewing death threats within the Threads platform, he MAY get sanctioned. Not banned, “sanctioned”. But if he does that to the Fediverse and especially on servers with already overwhelmed moderators, do you think that there would be consequences coming from Zucc for doing this kind of stuff outside the official Threads servers? No, nothing! Our moderators would surely ban him if they would find out about this in time, but imagine thousands of these kinds of accounts invading from Threads doing this constantly. This is not just Embrace, Extend, Extinguish, but it gets to Embrace, Raid, Harass, Extinguish
… Some people just like letting the corporate algorithm sort content by controversies and rage baits. Maybe they will make their own instances focused only on that, but I hope that they will not be worth federating with. Eventually some of these will go back to corporate platform and whine on how “bad and bleak is the Fediverse”. Good, keep whining and “advertising”. We don’t want people with that attitude here anyway.
They always have been