There comes a point where Youtube is not saving money by automating their content moderation but Youtube decides to keep pushing forward. At some point a competitor that is good enough will arrive and once large creators like this one, around 1.5 million followers, almost every video with over 2 million views, 8 videos with over 5 million views, leave they will pay attention. Until content creators have an alternative choice, Youtube knows they can implement any black box policy and ignore 99% of the backlash.
My personal theory is that they are doing manual review but only after an appeal. They definitely have software that flags videos for vulgar language internally, and I imagine only those parts and a couple minutes surrounding it are reviewed. They refuse to elaborate or make their methods public because they see it as a way to combat spam. It's becoming clear that the moderation team is mostly software at this point.
I have a different theory that Youtube is also classifying channels into kid friendly and unfriendly based on video content while ignoring the context the channel was made for. Game are generally much more popular among kids, and so this channel was marked as kid friendly. The channel is getting treated with rules that should only apply to kid targeted channels, unfortunately this benefits Youtube way more than the creator. Youtube Kids has ads.