No, because your hypothetical fishing forum is not "large scale", and because discrimination based on general topic does not suppress the free exchange of ideas the same way that discrimination based on the beliefs of the poster does.
If YouTube banned all health-related discussion regardless of what position the video was advocating for I would still disagree with that decision, but it would not be a blatant human rights violation the way their current policy is.
If YouTube banned all health-related discussion regardless of what position the video was advocating for I would still disagree with that decision, but it would not be a blatant human rights violation the way their current policy is.