To be blunt, I think you yourself are proving my point. You seem to be locked into this anti-Trump narrative and are interpreting everything through that lens: if I am not 100% against everything Trump stands for, then I must be for him. There doesn’t seem to be any shades of grey.
Your statement that I am suggesting we “accept everyone refusing to form rational opinions….” implies to me that you think that the only way someone could support Trump is because they are irrational. Nothing is perfect and if the choices are realistically between Clinton and Trump, there are some reasons for being pro-Trump. I just happen to think that there are many more reasons to be pro-Clinton.
My basic thesis stems from the fact that reality is relative. It is always going to be interpreted by our bias because we are always going to be getting just a sample of full reality. And further I don’t think it is really controversial to say that part of that bias is our emotional context. We are not robots.
Fundamentally we reduce polarization not by arguing (as the study you cited supports) but by being open to the other person separate from their point of view. It’s not acceptance of their point of view, it’s understanding of them. The latter is colloquially taken to mean “I think your argument is a valid one” but I am using it in the sense of “I know why you are behaving the way you are even if the way you are behaving is wrong”.
As I said in another response, it is futile for a Clinton supporter to argue with a Trump supporter but maybe not if they talk about how they both worry about their kids’ futures.