>How is this different from nightclubs having a high bar to entry?

The nightclub lets you know where you stand at the door. I took a read of tik-tok's about page, and it gives me the impression that they're here for everyone. Just a platform to share short videos. The author of one of the featured videos on that page looks like someone who may have been filtered out.

I don't think the analogy is completely off base, but we can judge tik-tok for being deceptive.