You are just describing a (good) recommendation algorithm. TikTok's is infamously good at figuring out your niches and catering to your taste by looking at your minute interactions with the content it shows you. My TikTok "for you" page has absolutely 0 mainstream politics, rage bait, or any other "normie" topics. It's mostly technically fascinating stuff and good absurd humor that caters to my absurd taste.

Optimizing for engagement is not inherently bad, nor does it necessarily result in socially suboptimal outcomes. My TikTok feed is very engaging without having to resort to triggering my anger.

A recommendation algorithm that only sticks to a handful of given topics (rage bait and furry porn?) is not a very good one.