The real problem is it ultimately taints their actual police / law enforcement work. There's now direct, firsthand evidence that they've expressed intent to us

The real problem is it ultimately taints their actual police / law enforcement work. There's now direct, firsthand evidence that they've expressed intent to use excessive force, lie, and otherwise disobey the codes and procedures they're expected to follow. Our legal system - particularly the judiciary - is predicated on very human-centric trust and credibility - our criminal verdicts are based on a standard of "reasonable doubt", for example, and of course "due process", "fair trial", and "jury of one's peers..." are all subject to human interpretation etc So when they are later required to testify about their actions or statements in court, the cross-examination will be brutally effective in order to create the reasonable doubt needed. So now they can no longer effectively do their job, because their very involvement ensures that it will be impossible to prosecute or punish any offenders - the very thing they're hired to do.