Also, there are plenty of cases of respectable scientists throwing away their credentials to make a ton of money making completely unscientific social media posts. I'm not saying this guy is doing that, but YouTube certainly need to do more than just look as someone's history and whether they're published. The article you cite is from 27 years ago. He will certainly have changed a great deal in that much time.
The sort of people who are happy to contradict authority were totally correct to contradict the WHO. The WHO weren't communicating best known evidence; they were communicating best known evidence that was acceptable to the Chinese.
YouTube removing people who disagree with the WHO is YouTube setting up a system that will amplify Chinese (or other large state sponsored) propaganda. And I can give an excellent example of a credentialed person who was correctly applying his credentials to warn people about an outcome that has, in fact, emerged. People like that will be targeted under YouTube's policy, which is not interested in correctness but in authority. It is enacting a policy that would have made this crisis even worse for me, because it would have removed the channel that I found out about it from. I am very thankful for having 45 days early notice.
How do I embolden text on HN? When a person with a PhD is talking about something related to their PhD it is imprudent policy to ban their content because it disagrees with a body who are (a) political, (b) purposefully slow to recommend things and (c) have covered themselves with something a lot less pleasant than glory with their response to the worst pandemic we've seen in a century. Turns out he has a biological Nature publication too [0]. I want to hear his opinion even and especially if it contradicts the WHO on coronavirus. I like to live dangerously; I'll take the risk that he isn't a specialist in respiratory infections and viruses.
YouTube has picked a policy that bans good advice if they don't like the tone or word choice on behalf of an organisation I believe the US government is trying to defund for incompetence. This is not a move that should inspire confidence in their fact-checking abilities. I'd bet they don't have doctors or nurses enforcing this policy either but it'd be nice to be wrong.
[0] https://www.nature.com/articles/366066a0