Hillary Clinton has made it clear that she thinks all white people and cops are racist. She has also said that at least half of all Donald Trump's supporter are a "basket of deplorables" who are "irredeemable." After rhetoric like that, there is no way the people she insulted will ever unite behind her as President.
The 'deplorables' would never support her regardless.
The Birthers, the white supremacists, the "Hillary killed Vince Foster" crowd, the ones who think that only blacks are racists, the ones that consider all Mexicans to be rapists....no- they will not unite behind anyone but one of their own.