I don't buy that for a second. The chief is projecting blame downward. Under different circumstances, an officer refusing to carry out an illegal order (presumably with relatively minor consequences) would face a career of parking meter duty. I'm not saying what they did was right; I'm just reflecting my view of human nature as it pertains to the chain of command.
Actually, I believe him when he say that no police officer has ever been cited for that. But I doubt there has ever once been an officer who made such a refusal. This was CYA talk by the Chief. No question about it.
The good thing about this is that it gives political cover and endorsement for the DA to go after Aguirre and any of his overenthusiastic subordinates.
The bad thing is that it ignores the fact that some of these cops were put in an untenable situation. If they stood up to Aguirre too visibly, they would be jeopardizing their careers and their ability to pay the mortgage. In hindsight, they all made a terrible decision. I'm sure it wasn't that obvious to them at the time.