This is not illegal.
First, this is neither conspiracy of sedition nor inciting an insurrection. A conspiracy would require the person to take some actions in furtherance of the crime. Inciting an insurrection would have to be "directed to inciting or producing imminent lawless action and is likely to incite or produce such action." (Brandenburg v. Ohio, 1969). To protect freedom of speech, courts have taken a very narrow interpretation. A person would probably have to encourage people to commit specific crimes in accordance with an organized plan for a full-on rebellion. In the video he isn't telling anybody to do anything. He is just saying what he thinks Trump and others will do.
Deleting the videos from YouTube is not destroying or concealing records with the intent to impede or obstruct an investigation under 18 USC 1519. That requires that the person act knowingly to impede an investigation. That means the "person must at least have an inkling that he is the target of an investigation. Without such knowledge, that person only knows that he committed a crime and the federal government may or may not detect it. He knows only that a prosecution 'may or may not happen'" (U.S. v. Dunn, 2006)
Federal agencies have not said they intend to charge anybody with or investigate anybody for inciting an insurrection, let alone this individual. Nobody has been criminally charged with inciting an insurrection in relation to the January 6 attacks. I don't think there is even an inkling that this person is the target of an investigation for inciting an insurrection.
There is also the question of intent. The destruction or concealment must be done with the intent to impede or obstruct the investigation. I don't know if the video is being taken down by YouTube or even at the demand or request of YouTube. Or maybe even out of embarrassment that the predictions made in the video didn't come true.
Someone deleting this video from YouTube is not criminal.
