I'm from California as well. Once the state CHP, a county Sheriff, or a local PD has issued a citation (or made an arrest), any further legal action is completely under the control of a District Attorney's office.
While the LEO involved can provide input to the prosecutors, they have no decision-making powers as to plea bargains. It sounds like NY gives a lot more discretion to their State Police rather than their prosecutors.
The problem here is who has jurisdiction over the disposition of charges filed by the State.
In NY, it isn’t this judge, therefore the consent of the offended party, in this case the State of NY through the NY State Police, must be secured.
NJ on the other hand, has dedicated municipal prosecutors. They have the final say on plea bargains, though they usually ask the officers for his opinion before making a deal.
This judge may not have been within his powers in forcing this plea bargain on the representative of the people, but a superior court will decide it...