The establishment's greatest fear is that people across the political spectrum would unite on an economic agenda that would work in the people's best economic interests (instead of the interests of the corporate political elite). That's why the 'bipartisan' political establishment uses divide and conquer tactics in every way imaginable.
Republicans leaders have always relied scapegoats to blame for their failed agenda of corporate greed and corruption. They tell their base that racial/ethnic/religious etc. minorities are the cause of all their problems, to divert their attention from the real causes of their problems (corporate greed and corruption).
Bernie Sanders has been attacked for trying to wake up this (and other) political constituencies who have been manipulated (against their own best interests) by the age-old divide-and-conquer schtick.
Bernie identifies the corporate greed and corruption as the real cause of their problems, then exposes the scapegoating for what it is, a tactic to divert their attention from the root causes of their problems.
Exposing the diversionary tactics of scapegoating and identifying the real causes of our country's problems should be a priority and it's what's been missing from our economic equality AND our civil rights/racial/ethnic etc. equality strategy. Who else could talk to these people and at least get them to humor the idea that they've been played?
What better solution could there be for racial/ethnic/religious equally and mutual respect than for people across the political spectrum to successfully unite/team-up on an economic agenda that puts people ahead of corporate greed?
We've been trying to wake up these folks for a long time, and just when it looks like that a few of them might start to see the light, half of our base shuts the lights off, refusing to even hope for a united public that could stand (against corporate greed/corruption), instead of a divided public that will fall.
Not only should Bernie try to wake up Trump voters, it should be encouraged. What better way can we achieve our goals of racial/ethnic/religious equally and mutual respect than for people across the political spectrum to successfully unite/team-up on an economic agenda that puts the interests of human beings ahead of the interests of corporate greed