For me at least the main problem isn't so much this person/channel, you can always tell YouTube to stop suggesting a channel. It's the people that now realise this is something YouTube allows (or at least doesn't seem to care about).
Relating to reply girls, I really loved YouTube's video response feature. It's understandable why it went away, but it was still really cool to be able to find responses to videos. Now if I watch a video arguing for X and want to see a response I have to search "Response to X" or "X rebutted" etc.
"Although many users would click the "dislike" button on the videos, this was interpreted by YouTube's algorithm as legitimate engagement, and the videos would be ranked more highly."
For a similar issue there was a plague of "Reply girls" for a while https://en.wikipedia.org/wiki/Reply_girl