Now I think I understand

It would be too simple:

Since the beginning of the crisis I’ve wondered why the government has found neither the will nor the way to attack the root of the problem -- the people who borrowed money to buy homes they shouldn’t have bought.

... People would understand a lot of small payments to the guy down the street who doesn’t deserve them, and become outraged. Far better to throw trillions at opaque corporations, the inner workings of which no one still really understands.

The long-tenured politician cannot directly assault the voters head on. Instead, attack a third party, and subtly bleed the voters dry. And the more progressive the taxation, the fewer people are affected.