There is a really easy solution to this:
https://www.youtube.com/feed/history
You can delete individual views and searches from your history that are used to make recommendations.
Yeah I know and do that, which is great for cleaning up my own feed but it doesn't really solve the bigger issue of the proliferation if this stuff across YouTube as a whole which helps spread this mindless nonsense and make it seem more mainstream and legitimate than it really is. Especially when you can get an avalanche of these recommendations without actually watching one of these Far Right videos. Just watching anything political or progressive by another YouTuber will often times result in several Far Right counter videos popping up. It just really gets crazy when you actually happen to watch one of the vids themselves.
I'm not going to call conspiracy or anything, but it's one of the few topics this happens with for me on YouTube. I can watch tons of random shit and my feed won't change much at all.
I can watch a bunch of Safiya Nygaard videos and I get jack shit recommendations for other beauty or women's fashion channels. I watch practically a documentary a night and only a few items will pop up.
But I watch a Tropes Vs video and then at least a few counter videos will start showing up and if I accidentally watch one of those charlatans it then seems to fill up every recommendation slot.
I can only assume it has to do with the Tags people attach to their videos that YouTube uses behind the scenes to help match you with like topics, among their other metrics. I wouldn't be surprised if these people spam a whole ton of different tags for their vids, which is why sometimes recommendations will come up even after not watching anything seemingly related.
There also just seems to be a ton of these people all over YouTube. From big channels that have tens of thousands of subscribers and post all the time, to an abundance of random channels that picked up a ton of views for going after one big topic or issue but don't really have all that much else.