Private companies are free to curate their content as they see fit and you can choose to consume it or not.

These independent content creators and journalists can all self host.

Freedom of speech doesn’t mean that every view gets maximum amplification on private networks. It means that the government won’t take steps to repress the speech, which they aren’t.

Again, no number of bad faith arguments about popularity or awareness in consumer headspace make it a monopoly. You are not entitled to being discovered in competitive markets, and forcing suppliers to host your content is anti-competitive.