When it comes to small or medium sized police departments, the Lone wolf, single bad apple, argument about bad cops is almost always untrue. Bad cops don't hire on with small or medium honest departments that enforce standards, unless it's a very rare case of a new guy, they work for departments that allow that bad behavior or big departments where they can fly under the radar.
I won't name the cities involved but there is an Army base down south with 4 police/sheriff's departments in close proximity. 3 of them, it was known, if you wanted meth you dealt with PD A, weed, the deputies controlled it and anything else, the 'biggest PD in the area handled it. I personally saw cops from 2 different PDs, selling drugs from their patrol cars. Literally sitting in a bar parking lot and selling weed. The 'bigger PD' chief was convicted of selling drugs and guns from the evidence lockup. Think his officers aren't running their own side hustles?
One Sheriff's department down the road stopped sharing info on upcoming raids and warrants with those other 3 departments.
And it doesn't have to be something as bad as what I just wrote about. It can be something as 'minor' as 3-man PD falsifying work hours or running speed traps. Or looking the other way when another officer beats up somebody while off duty.
Unfortunately, those are the departments we see or hear about because the smaller PDs that are run honestly never make the news. Where I live currently, I've had nothing but positive interactions with the cops. Doesn't mean I've forgotten about the New Llano, LA cops pulling me over 7 times in 2 weeks and spending almost an hour searching my truck every time because I went out on a single date with a cops ex GF.