ACAB is a common slogan, especially in anarchist spaces. Should we really be using it though? It is a reference to children born without their parents being married, and due to christian morality is seen as inherently negative. It is effectively a slur. Do we really think that trying to enforce the hierarchies we are trying to get away from on others is going to help us? How have we allowed this slogan to become so common?
As an anarchist I think we should be defending these people, not punishing them with the hope of some of that transferring to cops.
I’ve never experienced that and known numerous people who could be referred to as bastard children.
I think you’ll have trouble revising the slogan based on this quibble, even if there is this well meaning reasoning behind it.
Anther example is Bitch referring to a female dog. Now it’s just slang and the only people that still refer to female dogs this way are older English, Americans, & farmers it seems.