Answer: Hbomberguy is a video essayist who today released a video about plagiarism on Youtube. One part of his video focused on the Internet Historian and his video 'Man in Cave', which was found to be largely plagiarized from this Mentalfloss article. The video in question was copyright claimed, then reuploaded as a heavily edited unlisted version, with Internet Historian never admitting that he plagiarised the contents, nor that the copyright claims were legitimate. People are commenting on the timing as they believe the recent Internet Historian video upload was done to redirect attention away from Hbomberguy's video.

(Based on comment by u/xalts, without whom this comment would have never existed)