It's kinda easy to jump on the obvious "Yes, fuck facebook" bandwagon...
But I'm curious on how they intent to implement this. How are the communities grouped? Would we have to federate with the entire Meta Instance?
If Meta would have some "Programmers group" community that actually has high quality content and comments (And not default Facebook comment quality) with informed/informative members it could be interesting to federate with those...
It seems a little early to completely reject the idea before knowing more about the implementation details.
Also, it does seem like a great way to get a lot of expose. Lemmy is still pretty obscure. If meta connects with Lemmy, that's an influx of a potential 3.74 billion people... A bunch of those people might click through to smaller communities of their interests (like programming) and discover instances like that.