Not just YouTube comments, but videos as well have become automated or semi-automated to produce the most engaging content and maximize ad revenue. There are companies making millions by gaming the system. See the Elsagate scandal and TheSoul Publishing[1], the company behind those 5-minute craft videos and occasional Russian propaganda.
And of course similar things are happening on all social media platforms.
It's deeply ironic that the West built all these tools with the intention of "connecting" people, something that's still Facebook's main mission statement, yet its biggest effects have been exactly the opposite, causing division and distrust between people, and contributing to real world conflicts and toppling of governments.
Social media today is weaponized by political agents to spread misinformation and propaganda on an unprecedented scale and the platforms are paying them to do it. The current political climate in the US is no surprise. It was a coordinated psyops attack and its enemies are laughing at how easy and inexpensive it was to destabilize a nation compared to traditional warfare.
I fear that we still haven't seen the worst of it, and frankly I'm not sure what the solution is.
[1]: https://www.lawfareblog.com/biggest-social-media-operation-y...