ACAB as an acronym began in the early 20th century by workers who were striking in the UK. It is a term with a long, complex history behind it. Cops are the institution, so I'm not sure what you mean by individuals. Every member of the police force, from the top down, is a bastard. Every single one. There's no exceptions to this. The very nature of law enforcement is being a bastard. It is a term that is meant literally. Law enforcement functions as a means to break strikes, to enforce private property and ownership of the means of production, to enforce rent and evictions, to terrorize the impoverished and the marginalized, to collect menial tax from the impoverished who cannot fight back against them, and above all else to act as the legal arm of state violence against working class people.
Individual cops may have done good actions. I'm sure there's a cop out there who's volunteered at a soup kitchen, sure. But that has nothing to do with him being a cop. That has nothing to do with the actual role he fulfills in day to day life, with the violence he enacts, with the system he supports.
The idea that police are holding back some tidal wave of horrifying crime is and has always been propaganda. Nearly every single woman I know has been a victim of sexual harassment or violence at some time in their lives, including myself. A lot of them have gone to police before. I don't know a single person for whom that did literally anything good for them. I know 1 woman who was harassed literally across the country by people including police officers who said she was lying. The police don't prevent murder. They don't prevent violence of any kind that's literally not their job. More often than not they are the ones committing acts of violence for which there are no repercussions.