EEE stands for embrace, extend, extinguish. This is the embrace step, where everything is all sunshine and flowers. Actually the whole thing is sunshine and flowers, just the last step happens in that shaded area where nobody is paying attention.
But anyways, they embrace it and it seems like they are supporting the good thing.
Then they extend it with new shiny features. They are a large company and can afford to throw a bunch of developers at the project. This seems like they are doing more good, but the subtle thing is that now development outside of what they are doing is dictated to a degree by what they are doing. Sure, others can ignore the new features, but if they are important to users, doing so will mean that more users move over to their platform.
They can also adopt proprietary features that cost licensing fees to use. Or use their own. This essentially locks other devs out of those features, kinda like when a company decides to charge a ridiculous amount for access to their API, you either go along with it or you lose access to that API.
Once they have a lion's share of the larger platform's user base, they gain some power over the platform itself. They can start dictating things otherwise they'll cut dissenters off.
Of course, the next question is why would this be any different from just defederating with meta right now? It mostly comes down to inertia and people getting used to things. Say your friends are on threads and you're on some other non-meta instance. If you aren't federated, then you have other ways of communicating with your friends that you use and are used to. But if you are federated, then maybe you use the platform to communicate with your friends. Now all of a sudden there's a demand from meta to send Zuckerberg-compatible energy credits that would leave you defederated if your instance doesn't comply.
In the first case, meta's demands don't affect you at all. In the second case, ignoring them would disrupt your routine, which will be frustrating and that frustration might get targetted at meta or maybe it will be targetted at the instance when they decide to ignore the demand and defederate. Now multiply that by thousands of users and you might be able to see how having a connection with meta might give them the power to disrupt instances they have no direct control over.
Now that said, I don't know how much power meta will be able to build here. Personally, I already like the feature set they've got right now and think it only really needs tweaking. Reddit adding features to make their new site more attractive never even slightly tempted me to stop using the old site or an app that had nothing to do with the company. Maybe I'm lacking imagination, but I can't think of any features that would both attract users en masse, would be difficult for other instances to add, and would be something that I'd personally want. And any threat to remove meta's userbase from the fediverse sounds like threatening me with a good time.
So I lean towards defederating but not because I'm worried about meta eventually ruining this but because I think they will immediately ruin it by making it too popular. Kinda like Reddit's growing popularity over time seemed to correlate with a decline in average quality before even taking the admins and mods into account (though I'd bet that the growing popularity also contributed to those declines as well).