The term "African-American" was unheard of in the early 60's. I didn't start hearing the term until the early 89's.
It's has a lot in common with Dan Rather's phony National Guard papers that were produced using current technology as opposed to what was actually available at that time.
Because it was produced recently (by Hawaii). It has never been (seriously) claimed to be the original or a photocopy or scan of the original.
The forgery shows the father’s RACE as AFRICAN.
not, as you wrote, African-American.