Yes, both are infringing 1st amendment. It’s not because GDPR seems more acceptable than it’s not built on bad premises.
The First Amendment protects you from the government. Facebook censoring you is not prohibited by the First Amendment. More broadly, I don’t see how GDPR interferes with one’s right to lawful political speech.
But I still don't see the connection with the first amendment.
Edit: come to think of it I'm not even sure it protects them, but again, it certainly doesn't require them to store or transmit anything.