A corner stone in science, which goes far back in history, is trust. In order to understand anything we have to put trust in established facts, in experts and common understanding. Part of building science is building trust, and censorship has a strong negative impact on trust. If we go back to the analogy of poisoning the well of knowledge, censorship destroys people trust in the water itself.
To take an example of why this new Youtube policy might be problematic, could we still have a video about the risk in Postal voting? In the UK election in 1990, it was estimated that 50% of postal voting arriving from Ireland was fraudulent. Trust in the voting system was at an all time low. As a response the voting system was changed and identification became a requirement in order to vote. Trust in the election system went massively up, and suspicion of fraud went down. A decade later the UK government removed some parts of the requirements, but for Ireland the requirement still remain today. Should an opinion that the US could learn from the UK past experience with postal votes and voter trust be censored, or would it poison the ability to discern fact from fiction?