There are dozens of channels specifically based around torturing baby monkeys - either pretending to save it from a dog (after filming it being bitten and shaken in the dogs mouth for several minutes), or putting it through other forms of abuse under the guise of "looking after" it. There are people/groups trying to fight against this[0], but YouTube has ignored them for years.
But it even gets worse than that - a second "revenue stream" for these people involves private facebook groups full of people who enjoy watching baby monkeys getting tortured and killed, and will pay people to have them record videos of it.[1][2][3]
[0] Recent petition that I just found via Google, but there are many groups trying to bring attention to this: https://www.change.org/p/youtube-make-youtube-stop-all-anima...
[1] https://www.ccn.com/youtube-has-a-vile-monkey-torture-commun...
[2] NSFL: https://twitter.com/protect_wldlife/status/14243019790446141...
[3] https://www.thesun.co.uk/news/14032495/youtube-baby-monkeys-...