he should be sanctioned up to throwing out the cases...
That's his goal, but he has to put up the appearance of a fight to make it "look real." His mission is to keep the evidence out of public view, including keeping it out of trials.
The government is better off losing trials and hiding evidence, than it is in showing the evidence. But it can't appear to be voluntarily throwing the fight.
The DA has inserted a condition into the discovery process that exposes the strategy of these huckster attorneys who want to deliberately leak evidence in an attempt to taint the jury pool and force a change in venue.
This waiver tactic is either acceptable or not in the eyes of the court, but it has nothing to do with the guilt or innocence of those bikers who were arrested. The notion that charges will get thrown out over this matter is absurd.