IMHO 'beliefs' only go so far you need a lot more stuff to back up your campaign you need charisma, a good campaign team, tons of money, lots of influence to get endorsements, donors, donations; and more, I bet there been plenty of people that think we need "true X" , but those people either don't do well in polls or not as well as the moderate candidate and the true X loses primaries to the point the moderate guy( or whomever is deemed electable to win) gets the nominee .
I think usually people are going to choose who is most likely to win. Plus if the candidate can get away with more further to the left or right views( like what Hillary can) they can do and most likely people will vote for them. In Hillary's case, she supports issues that many Americans already agree with and if she needs to she can probably get some liberals on her side if she plays her cards right. Bernie is far far behind Hillary regardless of what excuse, to think that suddenly she lose like dozens of points and which most of that goes to Sanders is crazy. IMHO, some liberals are just idealistic. Some cite that Hillary was sure to win in 2008, but I think some people here have evidence that it was closer than what some thought. I think Hillary's support is unprecedented is what one article said, or perhaps I read wrong.
We all assume who as a chance, we never know for sure, but looking at evidence when it comes to the electorate and campaigns, there can be educated guesses and analysts.
The reason is as I already said; I think most people are center right or center left. These are national elections not state or local were crazies can get away with it.
So basically, some liberals or some people that support conservatives can believe what they want, unless they have factual evidence to back up their assumptions, they are just bullshitting. Using "I feel" or " some random person(s) I know supports this X candiate " arguments doesn't mean jack.