1) GitHub doesn't owe us the details of the investigation - what difference does it make to anyone apart from creating more fodder for gossip? This is an internal company matter.
2) Regarding Tom's "threat" - This is pretty much the largest "resolution" that could've come out of this, right? Some of Horvath's allegations were true and a high-profile founder has resigned. The way I read it was: What more is there to do? I think that's what he means. "I've resigned, isn't that enough? If you want to keep pursuing it, what's left to seek? At that point it's personal and my wife and I will respond appropriately."