It looks like almost all polling institutes have decided on a D+5% to D+7% model. That is as much as or more than Obama got.
The only way you can even come close to that result with a very unpopular candidate like Clinton is either that Trump scares so many voters, or that they try to correct for vote fraud.
Personally, I do not buy any of those arguments.
It has to be ideological.
Ignoring data or reinterpreting it to fit with they hope will happen.
Jake Novak wrote about it about a couple of months ago and termed the effect groupthink or confirmation bias.
They’re all liberals and they all think alike and none of them check the other assumptions to be sure they still match with reality.
During World II, Allied military brass did the same thing by dismissing signs right in front of them the Germans were prepped for a breakout offensive in the Ardennes.
That intelligence blunder cost thousands of lives. The pollsters’ blunder at worst will cost Hillary the election.