The channels in question aren't accused of containing false/misleading videos, they're accused of containing disallowed facts. Noone disputes that modafinil promotes wakefulness or that magnesium makes many sleepy.
So why is youtube any different?
Youtube only differs from other websites in scale. They are moderating content as we see fit. We can disagree with their reasoning behind moderation. But it's silly to act like they didn't have this right all along
(And that's what I see in this comment section. Comments like "why should youtube say what I can and can't watch?" I'm pointing out that those arguments are a dead end.)