They could respond to the specific points raised in the article. An “independent” investigation setup, run, and reviewed only by the alleged perpetrator isn’t exactly definitive - especially if you see the points in the article where they acknowledge the complaints are valid (note the non-denial about the only white person in the compliance group getting an offer which wasn’t extended to anyone else) and think about how a “cull through our historical data” might not yield the full story if, as described, not everyone had formal reports included in that data because they were not informed or discouraged from doing so. “Unsubstantiated” only means they couldn’t prove it, not that it didn’t happen or even that all of the possible evidence was fully disclosed.