Clarification Please!

This is a little complicated, and hopefully someone in my stable of commenters can explain it to me:

Antitax campaigner Grover Norquist advised a room of House Republicans on Thursday that a failure to extend the  payroll-tax cut would not be tantamount to raising taxes.

Okay, I can see that point of view, as long as you don't believe that extending the Bush Tax cuts would be tantamount to raising taxes. But if you do, what makes one a good idea and the other a bad one?