I'm pretty sure what they think is "we can loudly complain EU over-regulation is stifling innovation and try and get the public on-board by showing them everything they're missing".
They don't want to be sued in the EU for releasing a model. One way to do that is by not releasing it in Europe.
It's the same reason a lot of websites block the EU rather than risk being sued under the GDPR.
I'm not convinced.
The GDPR can absolutely be applied to foreign companies https://gdpr.eu/companies-outside-of-europe/ but even if it couldn't, Facebook is an Irish company specifically so they can avoid American taxes. I do not think the EU will have any problem with jurisdiction.