It's really trippy to reflect back on my pre-ACAB days. I recognised that the ways things currently work is far from just, but I was still in the "surely not all cops" mode of thinking; even if I understood how much of this injustice is a systemic problem. Whilst it was several years ago now, it still feels recent enough that I am baffled at how misguided I was to hold the beliefs I did and still consider myself anti-ACAB
I remember vividly that one day, it occurred to me that if ACAB seemed excessive and unreasonable a to me, that perhaps I was operating on incorrect assumptions about what ACAB actually meant (because me being wrong surely is more likely than everyone who says ACAB either being deeply misguided, or inflammatory edgelords). This led to me googling "why ACAB is right" and finding a lot of things that made sense to me.
I don't know where I'm going with this. I think perhaps my overall point is roughly that I think it's good to label these things with ACAB, where appropriate, because whilst the acronym itself doesn't have much explanatory power, it is useful as a distillation of a bunch of beliefs about the justice system that are actually somewhat commonly held. It makes me think of the saying "you can lead a horse to water, but you can't make it drink". Years ago, I was a silly horse who complained of thirst while standing next to water; sometimes it's useful to say "dude, you're literally standing in water".