Why Did Fox news Call the Oil Spill " Obama's Katrina " And why did they not call Katrina " Bush's Katrina"?

Fox news attacked Barack Obama all summer long, criticizing everything about the oil spill. Anytime something goes wrong, it's Obamas fault. Christmas Day bomber, Obama's fault. Oil Spill, Obama's fault. They will jump threw hoops to try and pin all the blame on him for any mishap that comes abroad.Which they have a right two, but I do not understand why they were calling it. " Obama's Katrina"... For 1, it was the Republicans who were Championing Offshore drilling. Sarah Palin, Michael Steele, and Mccain, every 5 minutes it was Drill baby Drill. Fox news never pointed the finger at them for the Oil spill, Or even brought up the fact that they were pushing for it! And as for Obama, he was never really for offshore drilling. Why Would they all attack him when The Problem came up, after all, it was a project these people supported?? Then when He tried to introduce a moratorium, they were against that??? Also, Why were they saying it was Obama's Katrina? 1,836 people died in total From hurricane Katrina, .. And 6000 Pets .. How do you compare the oil spill to Katrina? I never remember fox news calling 9/11, ' Bushes 9/11 ', or " Bush's Katrina". Why didn't they mock any other disasters that happened on Bushes watch and Tie his name in with it?