While Federal Government is charged with decision to lift travel ban, it's indiv states who decide what policies to implement for new arrivals.
Maybe I misunderstood something: I thought US CBP is responsible to enforce federal immigration laws. If a State has additional testing/quarantine requirements (e.g. HI), then it is up for the State (e.g. State Troopers) to enforce this. Where am I wrong here?
1st issue is agreeing a standard for validating someone is double vaxxed. UK and France have great apps, not so in rest of world.
Here I would assume that some Biden Administration bureaucrats just don't care or do not get the concept of the EU (and it's vaccine certification scheme).