Police become and stay corrupt because they know they are protected. "Thin Blue Line" and "Blue Wall of Silence" type stuff. Police unions really perpetuate this type of behavior by discouraging actual scrutiny of charges brought against officers. Police unions take a "we'll get you out of this, here's what you say and do" attitude taken towards charges all charges. And if they can't get all the charges outright dropped, the punishment is usually a slap on the wrist.
And don't get me started about "administrative paid leave".
AKA 6th Amendment right to counsel?
So no, not your 6th amendment right.
I concur with the point about how there's a general problem with police not doing their part to stamp out corruption, but that criticism should never extend to, "they get advice on how to beat charges? Outrageous!"
Edit: Also, IMHO, the general "right to counsel" extends to a defendant's general ability to educate themselves on the appropriate legal defense, even if it's not from their attorney.
Case in point: in the Freddie Gray case in Baltimore, the police had failed to serve search warrants for the officers’ personal cellphones.
And if they had been Wal-Mart greeters instead of union employees, they would've been fired on the spot.
And they hinder prosecution in a way that essentially amounts to blackmail. They threaten that the police force will become less cooperative with the prosecutors office. An office that depends of the force to do it's job. A prosecutor should be able to look into charges against a police force without fear of retribution by said force. But they can't. And police unions are the spokespersons/ringleaders of the entire scheme.
Only if we ignore the fact that the police unions either condone or vigorously defend the "police brutality and police corruption" every single time. Not once[1] have they censured a member for violating rights.
1. To my knowledge. I'd be happy (well, more like moderately surprised) to be informed otherwise.