Even without the crowd's reaction, this video is pure gold.
The Freudian slip here is just priceless. She meant to say she's going to raise taxes on the upper class, but accidentally says what she's really going to do, which is raise taxes on the middle class.
But the crowd's reaction is the best part of it:
Eewwww! The cringe!
HA HA HA HA HA HA!
The cringe is too much to bear!