While I would have thought the 1976 act superceded the 1945 act, it sounds to me like the 1945 act should have modifed the 1945 act instead of creating a separate act.
Not a legal expert but I play one on FR.
I think it might be the plague of being a legislator, you just continue to make new laws and consider old laws like monuments of other legislators who came before you. Striking down somebody else’s work would be rude. The idea is new laws only. More laws are good laws. All we need are new laws.