PSA: Watch in an private/incognito tab/window. If you are currently logged into your google account, this WILL pollute your watched history: https://www.youtube.com/feed/history
I think quite a lot has to do with machine learning working out that if you panic the human animal they pay attention to threats, and therefore to maximize engagement 'if it bleeds, it leads' (old newspaper maxim). Newspaper editors can (and might not) automatically apply a social-benefit heuristic or sense of social shame (not wanting to be a 'muckraker' or troublemaker), and machine learning may not even start with such a concept.
If engagement was maximized by turning viewers into cannibalistic humanoid underground dwellers (CHUDs), machine learning would simply make note of that and run as hard as it could in that direction, since it doesn't have a larger context in mind unless programmed to do so.
(Such a larger context is actually sort of controversial: lot of people demonize the very concept of social justice, and without it you get these hacks to maximize engagement by tapping into really unmanageable human/animal behaviors)