No. There's no 'free speech' obligation for a platform to promote your speech. Or to promote itself beyond what it sees as its own audience and mission. As you

No. There's no 'free speech' obligation for a platform to promote your speech. Or to promote itself beyond what it sees as its own audience and mission. As you note, the value of niche forums is the high signal/noise ratio--topical discussions stay (more or less) on topic.