Benchmark has a very strong interest in not publishing more negative stuff about Uber than they absolutely have to to gain control. They're the largest shareholder and need to liquidate their position in the near future; any wrongdoing beyond what they absolutely must claim to get a judge to hear their evidence behind closed doors is not in their self-interest.
They have a conflict of interest there. They need to do what they can to get as much control as they can without damaging the value of their shares. There is no fine line there, there is considerable overlap and no matter what they do their shares will drop in value. It's a risky game at best.
they would have had a material impact on Benchmark's decision is probably the weakest possible complaint.