Re: It's not "why", it's "how"
Somehow denying Donald the election is not going to happen:
1) When you put your "X" next to the Donald's name, you are actually choosing his slate of electors to represent your state in the college. Donald names his slate of electors for each state. Who are the most rabid Donald supporters in your state?--you'll find a good number of them by looking at the Donald's slate of electors.
2) Congress is controlled by Republicans and is going to wave the results out of the Electoral College through. Donald won the Presidency, and while a lot of Republicans in Congress would have preferred Jeb Bush or Ben Carson or somebody else, if they wave the Donald through they get to pass bills out of Congress and Donald will pretty much sign all of them. The only check on this is if the Dems can hold together a filibuster in the Senate. If Congress fails to validate the results out of the college, then they lose President Trump, his campaign and his more vociferous supporters, split the Republican Party, and look like loons bringing on constitutional chaos.
Meanwhile there is still Hillary Clinton in the wings with support of a tiny majority of the American electorate, much of big business and wall street and all of the media and entertainment industries. Congressional Republicans who think they can deny the Donald and put one of their own in the Oval Office would be playing right into the Democrat's hands