The YouTube app has non-standard and nonsensical UX on every platform. It's Google's fault, nothing to do with Apple.

Case in point: The YouTube app for Apple TV. Everything (pausing, playing, changing subtitles) has been done opposite to the standard player found in every other app. You cannot use the main button to pause and resume, for example. Recently they broke swiping. Normally, you swipe the remote to navigate between UI elements such as squares in a grid or in lists with a light touch. It's very fluid, like a touch screen. But the YT app has added severe "inertia" to touch gestures, and you now have to "fling" your finger on the remote trackpad to navigate. Everything feels syrupy and stuck.

YouTube and Amazon's Prime TV app are the two worst apps I've ever used on Apple TV. I believe they both use some non-native UI toolkit that doesn't respect native OS conventions and doesn't even try to. Pretty incredible given the size and budgets of these companies.