I am an attorney.

Your analogies don’t hold; no judge is going to consider those acts “publication” under the law. We’re talking about textual content here.

Good, expert attorney. Then tell us: is Meta a publisher under the law? If not, why not?

I’m guessing Meta and the public both have attorneys, and I suspect all those attorneys also know the answer.

You make it sound like there's a cut and dry answer to this. There isn't. Moreover, not all kinds of content are alike. There's content that Meta itself produces, and there is content that 3Ps produce (UGC, or user-generated content), which is what Section 230(c)(1) of the CDA pertains to. (Apologies for mentioning the DMCA in my previous response, I erred there.)

It's an interesting question as to whether Meta's act of selective republication of others' content constitutes its own content. This matter hasn't been adjudicated; I expect it will be in the fullness of time.

Parties and their attorneys disagree on legal and factual questions all the time. Meta has a position; others may differ. These disagreements are why we have a dispute resolution system (i.e., the courts) in the first place.