The video is captioned if you want. But the TL;DW is that there's an ethical spectrum of security content; on one end is sketchy content that has little educational value - like, say, a tutorial on how to make a phishing page - and on the other end is educational content that could be applied maliciously but isn't intended that way - like a general web programming tutorial (or a DefCon talk). YouTube seems justified in demonetizing or removing the former type of content, but the difference between these two types is not always obvious if you don't have a security background, and so it's expected that there will be some false positives / negatives in YouTube's filtering. In practice, educational content (from LiveOverflow, for example, and from the other security channels he knows) hasn't been banned, and the few false-positive bans appear to have been reverted quickly, so it seems like this is largely a non-issue. If YouTube actually starts blocking educational security content, and not being responsive to appeals, then this would worth being upset about, but right now it seems like a non-issue.

(Note that YouTube has plenty of other problems; I'm just summarizing LiveOverflow's take on this particular controversy)