And yet she still got more actual votes than Trump.
I agree with you that people aren't rational...but what you are failing to explain is your theory that Democrats only vote for Trendy Candidates. Registered Democrats vote for the Democratic Candidate. Registered Republicans vote for the Republican Candidate. "Trendiness" doesn't really come into play for these people.
If Trendiness is a factor at all...it comes into play regarding people that aren't really attached to either party.
When it comes to actual Trendiness...Trump is the winner. Hillary may be a female...but she acts and talks like every other politician. Trump, on the other hand does not. He didn't run a traditional campaign, he said and did things that a traditional politician wouldn't do.
If Democrats wanted a "trendy" candidate...Bernie Sanders would have won the nomination. He's an old white guy sure...but, like Trump, he wasn't acting like a traditional politician.