To me... it is about survival.... Hillary may turn out to be a terrible president, and in four years be ousted... we have survived bad presidents before, it sucks but we will live through it.
Trump however (And no I am not talking about media and speculation) in his own words makes himself a president that increases the chances of the country falling down and not having a life alert to get back up again (Bush almost got us down that low but we lived through it).
Hillary is a politician, she has been in public life for 30 years and no would not be my first choice. But she has withstood about everything the media, other parties, and society has thrown at her and is still standing. Is she corrupt? Is she beholden to others? probably... which makes her as I said a politician. If she has proven anything though is she will pull through.
I am sorry that the 3rd parties could only pull up an ignorant dunderhead and an anti-vaccine flower child. Maybe just maybe in 4 years, we will have another choice. But for now... I have to go with what I can live with, that is Hillary.