There is nothing Unconstitutional about State Enforcement of a federal law.
Here, let me give you a few examples:
Legal Drinking Age - 21.
National Minimum Drinking Age Act - Wikipedia, the free encyclopedia
Every State has LEO's that enforce this Federal (and State) law.
When a consumer purchases alcohol, they are *** required *** to provide
proof of age.
According to your logic and argument opposing Arizona's new law, and applying it to another Federal Law - this would be "age profiling" as well as "age discrimination" therefore .... unconstitutional.
The requirement to provide ID proving the consumer is 21 or older would also be unconstitutional and (like many here who have argued this point) the same as Nazism in that it is required to "show papers".
The fact that State LEO's enforce a Federal Law (in your opinion) would also be unconstitutional because Federal Law supercedes that of State Law, and a State LEO lacks the required authority.