I respectfully disagree that it is either true, or advisable, to offer blanket characterizations of Trump supporters as not very bright.  I referred to Trump as our Ignoramus in Chief, thinking it justified because I believe he actually is an ignoramus, who happens to be in the position he is.

Many Trump 2016 voters, however, have what I believe are legitimate grievances, shared with many progressives, about this economy and illegal immigration, for starters. 

Perhaps if progressives are able to demonstrate (at the levels of what candidates are saying publicly and in direct FTF engagement with citizens, and citizen-to-citizen discussions about public affairs) that we are listening, want to, and do, understand those grievances, and offer responsive proposals to address what is legitimate about them, we will be able to win some 2016 Trump voters over going forward.  Of course, this needs to be a two-way street.  It requires Trump voters willing to try to entertain the concept that some of what they current believe about "Democrats" or "progressives" or other despised others may not be entirely accurate.  (A sincere attempt to understand, at any rate, was what Arlie Hochschild made and wrote up in Strangers in Their Own Land.)

All the while not backing away one inch from calling out racist, sexist, and other misanthropic behaviors and public policies, and organizing to change public policies, day-to-day environments and practices of institutions, etc. for the better. 

I don't believe it is acceptable to kowtow or be quiet about racist and sexist behaviors and public policies in the course of "chasing" Trump voters with concerns shared by many progressives on issues such as the economy and immigration policies and practices.  I hope not only progressives, but all decent and caring citizens, will reject such a false choice.  We do not have to choose between race, gender, and economic justice.  We must pursue each of these.  

But don't take my word for any of the above.  You have recently cited Reverend William J. Barber as someone you admire greatly.  In his book The Third Reconstruction, he recounts some early lessons he learned.  Writing of a failed union drive in Martinsville, Virginia in chapter 2, he reaffirms his belief in the justness of the cause, of the end, while on his account learning valuable lessons about how to achieve them, the means (p. 28):

For me, my three years in Martinsville were the crash course in moral leadership that I didn't know I needed.  Our defeat in the union struggle sent me to my prayer closet and taught me how moral dissent is central to my vocation as a pastor.  But it also helped me to imagine the kind of coalition politics that we were able to practice in a local campaign against environmental racism.  I came back to North Carolina knowing both the fights I couldn't run away from and something about what it would take to win them.  Only a fusion coalition representing all the people in any place could push a moral agenda over and against the interests of the powerful.  But such coalitions ar never possible without radical patience and stubborn persistence. 

And what was the internal barrier Barber concluded he needed to overcome?  Mistrust of white people.  Grounded in an incident that occurred when he was 12.  He visited the home of his uncle who had married a white woman in eastern North Carolina and looked on with him at night at a fiery cross illuminating a small crowd of men outside the window.   Of this, he writes (p. 25):

...I learned firsthand to fear white anger and the violence of white mobs.  For me, a twelve year old boy, it had been a matter of life and death.  

Fifteen years later, those patterns of mistrust and suspicion that had been written upon my young soul were being used by people in power to subvert my work for human freedom.  I naturally trusted the black workers and their pastors.  But I was suspicious of white workers and their allies.  I had good personal reasons for these inclinations, just as others had reason to trust their own gut.  But Martinsville showed me that Jesus' insistence that we love our enemies is more than an ethical ideal.  In the struggle for human freedom, it is also a practical necessity.  If love does not drive out the fears that so easily divide us, we will never gather together in coalitions strong enough to challenge those who benefit from injustice.

I don't believe it will be possible to make headway against economic injustice (injustices against women of all skin colors and males of color, in addition to white males), reduce inequality, and more broadly address deep and dangerous shortcomings in the way this economy is experienced by so many in our society, absent the ramping up of cross-racial, cross-ethnic, cross-gender coalitions which are committed to doing so at local, state and national levels.   As I interpret it, this is one central component of Barber's project, as well as that of others in our society.   

It is not comforting (although paradoxically, it is also source of hope) to me to believe, as I do, that among those whose support for such an effort is necessary are some who voted for Trump in 2016.  One of the implications of this conclusion for me is to try to refrain from broad brush negative comments about all Trump 2016 voters, however tempting this is at times.  It is very tempting at times, because some of what we see is so repugnant and unacceptable.  I probably have failed to check myself at times.       

As to Trump himself, and other miscreants in his Administration, Congress and the media, that is another matter. 

And, again, to reinforce, because I am at pains to try to avoid being misheard or misinterpreted on making such a statement as I did above re Trump voters which likely will trigger strong disapproval or disagreement from some reading, possibly including you: I am not in any way suggesting support for suppression or withholding of criticism of specific racist and sexist behaviors, from whatever source, in the name of trying to create, develop or grow such a coalition(s) 

Apologies in advance if I am attaching far too much, or just too much, significance to this particular comment about Trump supporters and it is not reflective of your view.