law enforcement officials who support the law say that the boards subject their officers to unwanted scrutiny.
Exactly. The thugs, thieves, murderers and rapists are uncomfortable with the fact that the public is becoming aware of the fact that they're thugs, thieves, murderers and rapists, and they want to go back to being able to beat, steal, murder and rape with impunity, and that requires eliminating oversight. So they're actively moving to eliminate meaningful oversight.
It really is just that simple.