It reminds me of that scene in Heat, where Nate the fixer is telling Neil McCauley not to take too many risks. He reminds McCauley that Detective Hanna can hit or miss, when he goes out to catch a criminal. Maybe Hanna gets his man. Maybe he goes home empty-handed. Either way, tomorrow is a new day, and he can try gain. But McCauley? He can't afford to miss even once. He gets caught, he goes to prison. No going home and trying again the next day.
Now, Detective Hanna is a scumbag. He's a coke addict who poisons all of his personal relationships. He lives for the thrill of hunting down people like McCauley. But that doesn't change the fact that McCauley cannot afford to get caught by Hanna.
Similar thing here. In this metaphor, Cambridge is McCauley, perpetrating shenanigans and trying to get away with it. But there's always some scumbag out there, some racist prick who's just looking for an excuse to take them down. Cofnas can hit or miss, but Cambridge can't afford to miss even once. In this case, Cambridge's miss got someone killed.
If Cambridge actually did have strict hiring practices, they could have - should have! - circled the wagons, produced receipts, and done everything in their power to uphold Arday in the face of such baseless criticism.
In fact they did do everything in their power, which was nothing, because the criticism wasn't actually baseless.
You will do nothing, because you can do nothing.
- Viggo Tarasov