There's also the issue of "poison the well", which is starting to crystallize more clearly to me nowadays. The process is thus: you start with any random youtuber and comment somewhat reasonable center-right first, then some other bot goes full 'SJW this and that', and see which one the tuber bites on. When you have a hook on the second kind, you just go further and further into alt-right territory without the video creator realizing this is going on -- because why would they.
The secondary function is that any such comment will be a signal function of 'going offrails' to anyone with any sense. Youtube has a huge amount of data to work with, allowing for much more effective targeting compared to Google ads. The other equally effective tool is Facebook.
The reason I'm mentioning it is because I find this behavior in most comment sections, and it is almost beat for beat similar to radicalizing people into say, an 'Islamic' cult / terror group.
There's no winning move here by individuals other than cutting out the real alt-right channels. This pattern has to be stopped from the top down, so either YouTube finally realizing it's running a terror recruitment network, or the state forcing them to shut it down. It might be hard to do, but an easy start would making disabling comments on videos the default setting for uploads. Another would be forcing new channel to self-moderate their comments for a while, so that they get an idea of what happens in them, and are perhaps more likely to see their dangers.
It's particularly noticeable with a channel run by a woman or minority that moderating is necessary, but also quite effective in making comments nice, reasonable, and readable. Unfortunately, being white men from a state (or country) nobody cares about, RLM's comment are the standard free-for-all and reddit is -- of course! -- even worse. So some damage will always get in there.
I know this a bit of a side comment for what is basically just "uneducated white American men", but that process is definitely part of it. The fact that Rich and Jack play video games puts them at greater risk though. Because that's a thing now. And I hate it.