I wouldn’t say kbin would be harmed necessarily even if maybe just a tiny bit. A good amount of the users on Lemmy (can’t say much about kbin hadn’t tried it yet) *hate* threads. So as an alternative to Mastodon, that would actually more likely score them points not detract from a user perspective.
Most likely, for a user to be on kbin or Lemmy you either come from Reddit, or you come from Mastodon so the users would had likely made up their mind on separating themselfs from major platforms, that likely includes threads.
@FinchHaven @ThatOneKirbyMain2568 what I meant by that section you quoted from the post was, if Meta were to influence the development of Mastodon. If you switch to Firefish or others mentioned, you would probably have a more preferred dev team then what could happen to Mastodon with Meta.