Because there's never a negative consequence...

If the process even starts, cops nationwide stop doing their job completely.

Imagine if charging a fireman for arson meant firemen stopped responding to calls.

Or if a single malpractice suit stopped doctors from treating patients.

Cops are essentially a gang, they've been acting like it for decades now. The only time a cop will admit another cop did something wrong, is if that first cop was a whistleblower. Anything except speaking out against cops and they all close ranks to protect the "bad apple".