It isn't NASA's job. They provide all the relevant technical information if you could be bothered to read it. Do you honestly think US tax money should be spent on debunking woo woo?
Just to add something here, NASA was planning to commission a book about the Moon hoax claims once, and there was a public outcry about spending tax money on it, so they abandoned the idea.
I think the problem was that the author was sincere, and would interview independent scientists....
That would get him some serious doubts, and they realised they made a mistake. Then these people knew why NASA kept the lid on it all for so many years.