IIUC you're suggesting people -- academic lecturers, no less, not professional streamers -- splice out sections of their lecture, replace them with a content warning, provide a contextual link to the "risky" content, and then hope that people will follow it, jump right back to the original lecture, and then come back? (And that somehow that link won't trigger the same YouTube content flag, b/c obviously they're going to at least broadly categorize outbound links to combat spam.)
This (meaning HN) community regularly nerds out over SEO, landing page optimization, and zero-friction payment flows. Why should we expect educators to be successful delivering complex content in an approachable way if we're also going to require them to carefully slice their content into "acceptable" and "NSFW" segments and deliver them separately, even when the original lecture was linear?