Because, of course, he campaigned to the Electoral College (put advertising effort where the most Electoral College votes could be leveraged). Why the Democrats didn't do this is appalling.

> Because, of course, he campaigned to the Electoral College

Regardless of the validity of this argument as to Constitutional legitimacy, it's inapplicable to th claim made upthread which is that “the people chose him as their President”. They did not.

The electoral college determines the presidency, so Trump and Hillary campaigned for the electoral college, and Trump won.

If the popular vote won the presidency, Trump and Hillary would have campaigned for the popular vote, and there's no way of knowing what that outcome would have been.