"When the looting starts, the shooting starts" is a phrase by Walter E. Headley, the police chief of Miami, Florida, who said it in response to an outbreak of violent crime during the 1967 Christmas holiday season.
Donald Trump was already an adult in 1967 and even if he didn't know this was a dog-whistle for white supremacists.... Facebook doesn't have to amplify destructive ideologies just because the ones who relay it are ignorant. Otherwise everyone would invoke that excuse.