Indeed, however Google have said that their hiring practices for minority groups involve looking harder in those groups for candidates, not hiring candidates who don't meet the usual standards.
What I inferred from this, is that he learned that at least in some cases, there's aspects to Google's diversity hiring that they'd rather people not know about.
Now I don't know if this is false, true, or true within a small subset of Google; but his claim of the secret meeting does change the narrative somewhat in his favour.
Basically, you're asking for evidence so that he can prove himself plausibly innocent of a crime that there's no evidence for in the first place.