The not so slient minority (majority)

At the end of the day, all most politicians care about is money and getting re-elected, Bernie is rocking the boat. Bernie is not "business as usual".
Its hard to want to change the way government is working: All the perks and influence money can buy. Its easy to support and be friends with a Senator Sanders, one senator among many from a small state and limited audience. A very different situation with a president Sanders and a national audience (read: bully pulpit) and millions of people actually listening.
He might actually be able to do some of those things he talks about. Maybe not everything but some. Change is hard though. Doing the right thing for the American people is hard.

Make no mistake, this election is about "status quo" vs "change".

It is about your willingness to accept that 51% of Americans live on less than $30,000 a year and so what or want to Make that better. (https://www.ssa.gov/cgi-bin/netcomp.cgi?year=2014)
That .08% (yes, point zero eight percent) own 53% of all wages earned in 2014 or you want to make it more fair. (https://www.ssa.gov/cgi-bin/netcomp.cgi?year=2014)
That student loan debt is second only to home mortgage debt or you want to figure out a way to fix it that is more involved than just lowering interest rates. (http://mobile.nytimes.com/2015/03/22/upshot/were-frighteningly-in-the-dark-about-student-debt.html?referer=&_r=0)
You either acknowledge a canidiate with million+ donors in which 73% come from $200 or less and the largest campaign events this election cycle as valid and speaking For a large number of people or you can ignore it and call him a racist, sexist and a commie (sorry 'socialist' I get my red scare memes confused sometimes).
We have a canidiate committed to fixing a very broke system.
Not just talk about it as the progressive moderate-centerist who doesn't want to be like Denmark (cause 'Merica).