Spaw, I assume that you mean why hasn't the NAACP changed the organization's name to the "new" group referent.

My guesses are
1. the Board of Directors of that organization wanted to preserve that name since it was already a well respected "brand". To change it not only would have involved some economic costs, but would mean that the organization would have to spend time & money familarizing
the public with that new name.

2. the Board of Directors of that organization might have wanted to wait to see which name "won the contest" since in the mid to late 1960s there were a number of group referents vying for the title of the formal group name [Afro-American; Afra-American;
African-American]

3. the Board of Directors of that organization may have decided that NAAAAP [the National Association for the Advancement of African American people] was too many A's. I certainly think so.

:o)