Publisher, distributor, and platform are legal definitions that have been worked out through case law over a long period of time. Blocking content on a political basis as a non-internet content provider would be more than enough to get you treated as a publisher.

In pre-section 230 law, even blocking content for vulgarity was enough to get you treated as a publisher, that decision was Stratton Oakmont, Inc. v. Prodigy Services Co.

Eugene Volokh has a good summary of this at https://reason.com/2020/05/28/47-u-s-c-%C2%A7-230-and-the-pu.... You might want to read it so you don't make completely uninformed statements on the internet. You should stop doing that.