Now, Trump's motivation for pushing back so hard on this topic is quite clear: Trump has long been obsessed with defining himself as a "winner," and therefore he is very thin-skinned about any suggestion that his election victory is illegitimate.
Signs of this include his absurd overreaction to Jill Stein's recount efforts even though they were overwhelmingly likely to further confirm his victory, his campaign manager's annoyance whenever his popular vote loss is mentioned, and his team's repeated and completely bogus assertions that he won in an electoral vote "landslide" (his electoral vote win is the 46th biggest out of 58 in US history).
Naturally, then, when the Washington Post and New York Times reported Friday on a secret CIA assessment that Russian hackers intervened in the election to help Trump win, the Trump team very quickly decided to attack the CIA for even coming to that conclusion (combining this with, again, that bonus false claim that Trump had won "one of the biggest Electoral College victories in history").
Transition statement on claims of foreign interference in U.S. elections:
(New York, NY) - These are the same people that said Saddam Hussein had weapons of mass destruction. The election ended a long time ago in one of the biggest Electoral College victories in history. It's now time to move on and "Make America Great Again."
On a call with reporters Monday, transition spokesperson Jason Miller made the subtext text by saying this was part of a "narrative in the news" that amounted to "an attempt to delegitimize President-elect Trump's win."
Also on Monday morning, Trump made an even more bizarre attempt to rewrite history with the claim that hacking "wasn't brought up" before the election.
Of course, it was talked about constantly, not least by Donald Trump himself, who in July openly urged Russia to "find" Hillary Clinton's deleted emails from her private server.
Trump was also repeatedly asked about the DNC hacks during the election, and refused to endorse the reported conclusions of US intelligence agencies that Russia was behind them. "It could be Russia, but it could also be China. It could also be lots of other people. It also could be somebody sitting on their bed that weighs 400 pounds, okay?" he said at the first general election debate in September.
Then in October, the US Intelligence Community released a statement saying it was "confident that the Russian Government directed the recent compromises of e-mails from US persons and institutions, including from US political organizations." But that wasn't enough for Trump. "Maybe there is no hacking," he mused during the second debate. So this has been going on for some time.