[emphasis added]
So, no, Section 230 isn’t what protects you. It is BB’s policies and the likelihood they would object to a subpoena for your email address and IP addresses.
I believe he could under US law. It’s not a term of fact. But, admittedly, I’m not a lawyer, and even a lawyer’s opinion is subject to refutation by a judge who may decide otherwise. Also, you are equivocating on “get away with”, saying that frivolousness suits count as not getting away with saying something. There is nothing you can say that can’t be be taken to court with a frivolousness suit. You can literally be sued for anything. The question is whether or not the plaintiff is likely to prevail. And that is where Cory made a huge mistake calling people “criminal” absent a conviction, which can be “defamation per se”, and why he uncharacteristically backed down instantly and completely, no doubt under the advice of highly competent council.