Have we ever had video of a school shooting before? (A genuine question, as I don't think we have).
Also, about YouTube. That's literally just YouTube being retarded, videos not related to school shootings are being taken down all the time, so I wouldn't use that as an example in this case. It has to do with YouTube's new algorithm and their attempts to make the platform overly politically correct. The removal of videos and even whole channels is quite common over there, and it's why many content creators like myself moved over or are moving over to Steem/DTube/DLive.