If you wanted to prove someone has talent, you would point to them pushing out noteworthy things on a consistent basis. Sure, someone can be very talented but have only a single thing to their name, but it's just as likely they got lucky.
We know we have to take action and have begun a full
investigation. While that’s ongoing, and effective
immediately, the relevant founder has been put on leave,
as has the referenced GitHub engineer. The founder’s wife
discussed in the media reports has never had hiring or
firing power at GitHub and will no longer be permitted in
the office.
So it's not like they're completely silent. They said both the referenced founder and employee have been put on leave and the wife, who apparently was allowed in the office before this, is no longer. They didn't flat-out admit to anything, but it's not like they're totally silent.