Hillary disregarded polls as well and kept telling everyone her win was inevitable...
And for some reason lots of people walked away from 2016 believing that the right lesson is:
Always ignore polls you don't like
Bad polls mean the candidate needs to re-evaluate their stances and try to align more with their voters, not double down and scream at voters that they have no choice but to vote for them anyways.
That shit doesn't work, but we keep running candidates with a blatant disregard for what voters want.
This is what happens when the party only cares about donations, the people running the party have no idea how to get votes, just good at getting money from corporations and billionaires