The administration actually thinks that sanctuary cities do not preempt or interfere with federal law, yet this law does. Don’t look for logic or consistency. They go by the idea that reality is what they say it is for any one situation, and there are no conflicts. It’s a classic example of Orwellian doublethink.
You have misconstrued their position. They think that sanctuary cities do not preempt or interfere with federal policy, and, unfortunately, they are right. Sanctuary cities have codified current federal policy.