Acab is not about there being good cops that are drowned out by bad cops. Acab is that, by definition, all cops are bastards. There might be good people that become cops, but they either stop being cops or stop being good people, because it's a requirement of the job. Anyone who abides by the "thin blue line" to protect their corrupt buddies is by definition corrupt, and cops, by definition follow the thin blue line or they lose their badge.

Good cops either quit, turn apathetic, or get murdered by the bad cops. One bad apple ruins the whole bunch.

The problem with the 'good cop' is that they're either too incompetent to know who the 'bad cops' are, or they know and they do nothing about them, or there are too few of them to do anything about the overwhelming number of 'bad cops' (the real answer). But in any of these cases there obviously aren't 'a lot' of good cops.

I do feel for the few that exist, but police abuses have been institutionalized so even a 'good cop' is working against bad policies and will eventually fall in line with those policies or not be a cop for long.