Only a kook could claim the Apollo landings were a hoax.
Although we have the technology to where you might be able to build a believable hoax, the technology of those days was not up to the task.
Another problem with a hoax is that there were just too many people involved. Many of those people were not involved with the government and so had no reason to help with a hoax.
NASA is an open public agency, and has been since its formation. One of its main jobs is public information and education.
All of their launches (except for some military shuttle launches in the 1980's) have been announced in advance and open to news coverage. The entire process has been open to reporters.
During the Moonwalks, there were independent observers, who saw and monitored the entire process. For example, ham radio operators around the world heard and tracked the signals that could only have come from the Moon. Space observers noted and logged the engine firings and Independently calculated the orbits.
These same space observers, mostly in England, but many in other countries, are the reason we know about the secret launches from the USSR.
Maybe a country that had controlled media like the USSR could have tried to pull off a hoax, but there are too many Independent observers who compare information and would quickly uncover a hoax. And many of these observers are not friendly to the US and would relish the idea of being able to prove a hoax.
The conspiracy mongers constantly talk about hoaxes and cover-ups by the government, yet only Watergate has been uncovered.