Maybe both parties' intense desire for privacy in this matter has driven Google to this strategy.
The seeming ludicrousness of the result - Alsup's "go try again, harder this time" - is not caused by this case's parties playing badly. It is caused by poorly defined and understood laws surrounding what constitutes a defensible search. Data handling in this stage of legal proceedings is imperfect, and can be manipulated by both parties to drive up the cost of litigation, or to strategically avoid disclosing the key breadcrumb documentation that would otherwise have led to the smoking gun(s).
Edit: Please find the court reporter transcript here: http://www.documentcloud.org/documents/3533784-Waymo-Uber-3-...
Judge Alsup's comments are fairly aggressive in comparison to most commercial litigation, but the no-nonsense tone is par for the course.