I agree Trump is mostly a symptom of polarization (although I would say "what if"-based fear is more of a rhetorical tactic than a problem in itself).

Bottom line: we have some very severe systemic issues that allowed Trump to get as far as he has. Even if he isn't elected, if the issues aren't addressed, there will just be another Trump, and that one might be successful. So it behooves everyone to at least listen and try to understand what his supporters want and why they feel underserved by the current system.

We won't be able to do that if we write off everything Trump says as crazytalk. Clearly, his supporters don't see it that way.