If kbin.social can't handle the bandwidth of federating with Meta then it will defederate. But I don't run kbin.social, that's up to the people who run it. The question is "how do we feel about federating?" As in we the users.
And that's who I'm responding to here. A user who was concerned about the content that they posted being seen on Meta's servers. They're not worried about bandwidth costs, they're just worried about some kind of bad magic happening when Meta users see their posts in the context of Meta's instance.