I do imagine they have a dirty trick in mind and I’m not sure what it is yet. Perhaps they aren’t either.
There’s also an opportunity though. Threads users will get exposed to open source, independently-hosted alternatives they wouldn’t have heard about otherwise. Some of them will switch. If those projects can offer a better user experience than Threads, more of them will switch.
I suspect the angle is something around avoiding regulation, they were happy with the previous “we’re just a platform” arrangement where they could hold their hands up and waive responsibility for the content and users on it. Now that’s actively being remediated by various governments, I think they’re hoping they can make claims of reduced responsibility for what’s on their site if it can come from elsewhere in the fediverse.
I’m not sure about specifics, but my gut feeling is that this is the angle
