ACAB is bad messaging and nobody within the movement agrees on how literal it is. The same applies but even harder for Defund the Police. I also don't think the literal ACAB meaning is helpful because classifying all cops the same way encourages those who don't care about their reputation (ie. usually actual bastards) to stay, and discourages those who do care (ie. less bad cops) from staying, leading to the police force getting worse over time. It also means that the police force has no incentive to change, because they'll be labelled the same either way (although most wouldn't follow a reasonable incentive anyway, unfortunately). TL;DR: IMO your heart's in the right place but the consequences of treating ACAB as "absolutely true" instead of as an opportunity to make meaningful changes within the system is a mistake.