That makes about as much sense and the fire department trying to pull a building permit and stop construction 'cause someone is installing sprinklers. That's like the local police filing an injunction against you taking a drivers ed class.
Why are obama and his cohorts in crime so outraged? I think it is because the illegal aliens in the US were their ace in the hole. They were hoping to grant them amnesty, buy their vote with our $$$, and secure their socialist agenda for decades. Instead, AZ has brought the issue to a head before they were ready (when obama and crew were already down due to economic, credibility, and a host of other issues), forcing the debate, and framing it in a way the 'rats can't get under control (yet, but they are trying). That's the only reason I can see for obama and Holder taking action that is just completely indefensible by any reasonable measure. They look like idiots with room temperature IQs (which may actually be kind). They are in full-tilt panic mode to salvage their plan.
You are correct. They are attacking because they have to make AZ look wrong in enforcing the immigration laws to try to get support in Congress for shamnesty and 15 million instant Rat voters.