That is a COPPA compliance thing and is true on the regular YouTube app as well:

https://www.androidpolice.com/2020/01/30/why-youtube-videos-...

This is because of YouTube‘s obsession to build cross-platform, lowest-common-denominator apps, resulting in mediocre experiences across all the platforms they support, and rarely excellent on any single platform.

Their Apple TV app is basically a web view which doesn’t conform to any of AppleTV’s UI principles. Same as their YouTube TV app. It’s sad.

> Also the built-in reader mode makes most sites a much better experience.

True, but it doesn't improve page load times.