If I'm reading both the Apple prompt details and the Twitter statement correctly, what that tweet is saying is that Facebook will not request access to the IDFA at all, and will also not allow developers using Facebook's SDK to request it. This means they won't trigger ("adopt" per the tweet) the prompt notifying the user of tracking, since they aren't using the IDFA to track anymore.

The rest of the tweet goes on to describe how to comply with that policy from Facebook, and to suggest alternate methods for developers to track users on iOS, including Facebook Login or Advanced Matching.