Do we have it 100% confirmed that it was the Russians?
Hardly: Mook and Podesta were looking to deflect attention from Clinton and needed an immediate plausible answer. Obviously, their response will look dumb and deceitful if this turns out to be someone else. (And, honestly, given what we know about the technical details of the hack it could have been almost anyone.) But that could be weeks or even months from now, by which time the entire affair will probably be reduced to an inconsequential footnote.