Unfortunately, even if instance admins were to unanimously defederate, Meta—or any social media corporation—could create white-label instances to take their place, and we might be none the wiser of their control of them.
I don’t necessarily disagree with this idea, but they would have to justify the business case to their shareholders. As of right now, the idea of a whitelabel personal silo is a limited value proposition to people not already invested in the Fediverse. If it’s whitelabel, what will Meta do? Start a new company? Inevitably, people would figure it out, and go with something else.
It’s true that we can always choose to defederate from them. What’s to worry about is their meddling with the ActivityPub standard using their incomparably vast resources, and them making their own extensions to the standard in efforts to suck users back into the Borg. Things like that.
I said this a little further up in the conversation, but if Meta produces some horrendous, awful version of ActivityPub that only benefits them, what’s stopping the rest of us from forking the protocol or adopting a different one? If we never switch to their version of doing things, and there’s feature breakage between us and Meta, who actually loses here?