I normally avoid arguments about this, but factually you're incorrect.
There was approximately 61.4% adult voter turnout. Not only that, trump LOST the popular vote with only 46.1% of the ballots.
What this comes out to is that roughly 30% of eligible voting adults supported Trump. This is _nowhere near_ "roughly half of Americans".
(I'd add the additional factor that only ~130[EDIT: 250] million of the ~323 million US population is even eligible to vote. I don't mean this in terms of "Oh secretly all infants liked Hillary" but that it seems disingenuous to portray the numbers as an overwhelming popular mandate in the way you're suggesting. The data is simply not that comprehensive.)
EDIT: As newlyretired correctly pointed out I conflated the total eligible # (250m) with total voted # (130m) That being said, I still stand by the crux of my post.