You said: “Actually, that’s exactly what it does mean. It means that one state cannot subject to its own scrutiny the official acts of another state.”
A forgery is not an official act of any state. It is a violation of the laws of the state.
If somebody at Nebraska’s DOH started cranking out “official” birth certificates for people who don’t even exist, would every other state have to accept those BC’s without question? Suppose the Nebraska DOH claims that 5 billion children were born in Nebraska hospitals in 2010. Would the other states have to accept all 5 billion birth certificates? Would there be ANYBODY who would be authorized to question the lawfulness of those 5 billion birth certificates?
If so, then government bureaucrats are and always will be laws unto themselves. That is SO FAR from the government accountability that the Constitution is about.
Full Faith and Credit shall be given in each State to the public Acts, Records, and judicial Proceedings of every other State. And the Congress may by general Laws prescribe the Manner in which such Acts, Records and Proceedings shall be proved, and the Effect thereof.
I think that, unless Congress prescribes otherwise, if an Hawaiian clerk creates a false birth certificate that becomes one of Hawaii's public records, then the accuracy of that record must be challenged in Hawaii. I believe that so long as Hawaii treats the certificate as valid and accurate, other states are required by the Constitution to treat it as valid and accurate.