The head of the Big Apple’s most powerful teachers’ union flunked Gov. Kathy Hochul and “tone deaf” Democrats Thursday for socking working class New Yorkers with a $9 congestion toll — a week after the election where the party took a drubbing.

“It’s not what I expected to see Democrats doing a week after the election. It’s insane! Stop screwing the working class!” United Federation of Teachers President Mike Mulgrew told The Post, saying he will continue to press his active lawsuit to stop the congestion pricing plan.

It also puts Mulgrew on the same page as President-elect Donald Trump, who slammed the “congestion tax” as “massive” and “regressive” in exclusive comments to The Post earlier Thursday.