For example, useful debate around hydroxychloroquine. The studies continue proving that it is an effective treatment https://c19rmd.com/ and even the American Medical Association is considering changing their posture around it.

Sadly, the drug has been highly politicized and all positive discussion around it was banned from YouTube. The OAN channel in YT was banned for talking about it: https://uk.reuters.com/article/health-coronavirus-youtube/yo...

There are many other instances of YouTube censoring discussion that results in a harmful effect to society. For example, most popular channels posting riot videos were demonetized.

Essentially anything that deviates from WHO guidelines, that is to say conventional wisdom and orthodoxy...