The Mikado, keep in mind there was a lot of lazy journalism in the immediate aftermath of the election that didn't consider the considerable mail in vote in CA and the west coast and they rushed to the presses with lines about Trump winning because of lower turnout and that he got less raw votes than Mitt Romney did.
Neither of which was true. He got a lower percentage, but Trump got 2 million more votes than Romney and Clinton came close to matching Obama 2012 (was only off by 100,000 I think), and beyond that the substantial increase in third party voting, which was ignored.
So between the premature reports that didn't include the mail in vote, and ignoring the larger third party vote, lies the formation of this narrative.
Interestingly, Trump also received slightly less votes than the aggregate U.S House Republican vote total.