Most all of the DNC / Podesta emails are DKIM verified. That is a level of proof far beyond the word of a single security company with close ties to the FBI and the US government. I scanned through those two links you posted and I've read other interviews with Alperovitch, and I still have not seen proof that Russia was involved. Appeal to authority is not proof. With a password like "p@ssw0rd" it's not hard to imagine that many, many state-level actors and others had access to those emails.