The Twitter user told us that he deleted the original joke after he become "educated on the topic of mothers who are imprisoned and the affect that has, not only on them, but their families."
You're missing the point of ACAB. All cops are either bastards or they tolerate and join ranks behind the ones who are actually bastards - making them bastards as well. Whistleblower cops are not bastards, but they end up not being cops any more and often not being alive any more.