An important thing to remember with something like ACAB is, even if it's not literally ALL cops are bastards, it loses its bite if it's anything else. When we say ALL cops are bastards, we serve to remind the people who already at least partially buy into this belief that it doesn't really matter about the individual. It's about the institution. Anyone party to that institution is part of the problem, even if they're a generally decent person who, in a particular situation, did something commendable.
As far as getting the people who don't already buy in to buy in? Well,that's what these kinds of discussions are for. No motto easy to turn into a soundbyte is going to change too many minds, they're more rallying calls.
Further, unlike the other examples, "cop" isn't a fundamental aspect of their existence. Any cop, right now, can stop being a cop. I have no problem throwing shade at something someone can change. Dogs can't not be dogs. Birds can't not be birds. Houses.. well, they could be something else with a lot of effort, but it's fundamentally different.