ACAB & ACAC both span multiple english speaking countries, predate BLM days by at least three or four decades, and are hardly idiotic in the face of documented abuses of power by rotten apples, coupled with tacit acceptance of the bad ones by their wider fraternity.
No drama, I first encountered the acronyms on the 10th of June 1987 while hitchhiking - I was picked up by two lads just out of reform "school" one of whom had both tattooed across the knuckles of his two hands.
In classical times the same sentiment evolved from "Quis custodiet ipsos custodes", although the actual context of its appearance in Juvenal's poem it deals with the suspicion that wives will always be unfaithful, even via the corruption of those assigned to watch them.
