Perhaps because his words would be used against him in a court of law, this (click to enlarge):
Still the "Big Lie" about election fraud as the "Crime of the Century." Demagoguery, mental illness, sedition and pathological lying all rolled up into one sick monster.
BONUS: Shane Goldmacher notes there was another factor for the cancellation:
"In recent days, according to people familiar with the matter, it became clear that Mr. Trump’s news conference would not likely receive the kind of blanket cable coverage that he generally desires...."