Who stole it?
All those eligible voters who didn't show up. They are the one's who had no confidence in Donald Trump as president, but they couldn't bring themselves to vote for Hillary Clinton. Many of these believed Trump's accusations against Clinton even though they disbelieved everything else Trump said.
Consider that an extra 50,000 votes total in just three states would have given Clinton the election.
See "For Reeling Democrats, Now What?", Cathleen Decker, Los Angeles Times, 2016-11-10,
Were you one of these 50,000 non-voters? Did you steal the election? Did you help rig the election?
The only way you throw your vote away is to stay away.
Be sure to vote in 2018 to bring about a better balance in Congress.