The reason people see Clinton as left-wing is because her campaign and the American media used this as a cynical marketing tactic to try and convince people to vote for her. Anyone who pointed out the fact that she did not, in fact, align with leftist politics was accused of practising "purity politics" and of hating her because she was a woman. The New York Times ran an opinion piece telling her critics to "grow up". There was a general feeling amongst the media that there could be no good-faith criticism or dislike for her from a left-wing perspective. A lot of this spread onto social media too, not helped by the astroturf campaigns by groups like ShareBlue/Correct The Record.