Because you're lying about the claim being made. It is correct to say that Trump was elected by a minority of the total votes cast. It would be incorrect to say that he was elected by "some vanishingly small minority", but you're the only one saying that. Being elected by a minority is sufficient to sustain the claim that an institution is antidemocratic, particularly in an otherwise simple-plurality voting system. I'm sorry if there's some reality there you don't like.