I actually understand that about unions.  (I've been a member of one earlier in life).  That said, the Union could realize that there is both a problem and a risk for their people, and they could step up and help be part of the solution pro-actively.  I'm not talking about withholding support if an officer gets accused.  As in a trial, the officers are entitled representation.  But the Union could be out there aggressively promoting certain behavior modifications and discussions (even mental health help, which I would guess they DO support) such that fewer of their members would get into trouble.  

They should be promoting to their members that this job is NOT the job of a soldier.  They are not entitled to behave or talk like soldiers, and job is literally a different thing.