To be specific, the videos blocked are that of gaming reviews about Japanese-based games such as Attack on Titan, Hatsune Miku: Project Mirai 2, and BlazBlue: Chrono Phantasma. Granted some of these games you might not have heard of before, but it does go to show that it is possible that some videos that you want to watch may no longer be possible if you’re living in the US.
According to a notice provided by YouTube with regards to the blocked videos and how they are related to YouTube Red, “The overwhelming majority of videos on YouTube are accounted for in our agreements, but there are some partners who have asked for more time to think about their options. While we work with these partners to update their terms, we unfortunately can’t make their claimed videos available in the US.”
So basically right now it’s the onus of video publishers to get on board with YouTube Red, or start finding an alternative video hosting website if they wish to get their videos playable in the US.