I've definitely watched repair videos on tiktok. And one of my favorite (indie) tv shows was only on YT for some reason instead of Hulu or Netflix. My kid watches videogame playthroughs on YT, not twitch. And that's completely disregarding you can listen to music on YT.

When defining a monopoly you can't just say "only this subset of the market is the market we're considering" you have to look at everything it does. As the FTC just learned