"This is possibly true – but only to an extent. Congressmen and women did push him on whether GDPR rights – such as the right to data portability or to object – would apply to everyone, but he slipped out of those questions just as he did the ones on shadow profiles or tracking logged-out users."
From a purely European PoV that's something FB will have to work out for themselves. A better question will be what they plan to do to satisfy GDPR rights in Europe, including those of non-account holders.
If - and it's a big if - they can achieve that then they need to work out whether it's easier to simply apply them system-wide. That must be a question a lot of corporations will have to decide once they've taken on board the fact that the EU means business over this. And, if EU politicians didn't mean business before, FB and CA between them have definitely raised the profile of privacy.