And they viewed her as untrustworthy due to false news and other bullshit the Republican news basis prompted up. The left didn't help either considering half of them wanted a different candidate. And what can they do to broaden the message anymore? What's an issue that will appeal to the working white population?
No, they viewed her as untrustworthy because of the past 20+ years of the Republican Party characterizing her and her husband as that. It happened long before fake news became as prevalent as it was. The reality is that Hillary was perceived as dishonest, untrustworthy, and corrupt, which makes it hard for some voters to think she tried truly cares about them.
There's plenty in the Democratic Party message that can appeal to the white working class (minimum wage, health care, education). Problem is that many Democrats just wrote these voters off - why should we be surprised that they went to the only people that paid attention to them? Democrats have won some of these voters in the past - some even in this election. There's no reason it can't happen again.
But Kander makes an important point in that we should not and can not abandon other Democratic issues - things like LGBT rights, criminal justice reform, health care, etc.
If you want to mope around and act like things are hopeless, go ahead. It's not healthy nor productive, but if it works for you then that's fine.