No Slate Obama has not. Assange stated that the email leaked "there is no proof whatsoever" they came from the Russians. Obama is trying to transfer blame and keep the explosive nature of those emails that shows Hillary is a traitorous criminal.
>>> Obama administration has “removed any reasonable doubt that the Kremlin has weaponized WikiLeaks to meddle in our election and benefit Donald Trump’s candidacy.”
Normally, facts remove doubt, not “the Obama administration.”
I took the quoted statement to mean that the whole story was planted by the Obama administration. Maybe that’s because I want to read it that way.