Prior to early July, when the FBI began receiving Steele-dossier reports (which the State Department would also soon receive), the intelligence community — particularly the CIA, under the direction of its hyper-political director, John Brennan — had been theorizing that the Trump campaign was in a corrupt relationship with Russia. Thanks to the Steele dossier, even before Downer reported his conversation with Papadopoulos to the State Department, the Obama administration had already been operating on the theory that Russia was planning to assist the Trump campaign through the anonymous release of information that would be damaging to Clinton. They had already conveniently fit the hacked DNC emails into this theory.
Downer’s report enabled the Obama administration to cover an investigative theory it was already pursuing with a report from a friendly foreign government, as if that report had triggered the Trump-Russia investigation. In order to pull that off, however, it was necessary to distort what Papadopoulos had told Downer.
To repeat, Papadopoulos never told Downer anything about emails. Moreover, the Mueller report provides no basis for Papadopoulos to have known that Russia was planning the anonymous release of information damaging to Clinton in order to help Trump; nor does the Mueller report allege that Papadopoulos actually told Downer such a thing.