Maybe they should be there for people who seek them out, but YouTube shouldn't be recommending them onto people who didn't previously want them and who might not be approaching it skeptically.
Why is it YouTube's business to judge truth and falsehoods and provide a manicured walled garden? That seems like an avenue for all sorts of manipulation, censorship, etc.
YouTube is already an avenue for all sorts of manipulation. They recommend harmful crazy conspiracy videos to unsuspecting people all the time right now. (9/11 conspiracy theory videos might just sound silly, but I'm also thinking of stuff like racially-charged holocaust conspiracy theories and baseless anti-vaccine stuff.) I think you're way too optimistic if you don't think those are likely converting many people at YouTube's scale.
Just because this is the result of non-action by YouTube doesn't make it okay. YouTube becoming a moral arbiter isn't a perfect situation, but it can easily be better than the status quo.
I don't find this true at all. Youtube is pretty biased in recommending videos closely related to what is in your history. It's pretty rare I get something that is not directly related to a recently watched video (this is clear because if I delete said video from my history the recommendations go away).