BS. We've discovered there's significant amounts of water on the Moon, we could be investigating that. We could be setting up real time cameras there to observe earth 24/7. We could be doing experiments with atomic clocks to check how orbital periods vary, and many more. We could be building launch infrastructure there. we could be investigating lunar geology, such as underground lava tubes whose existence has been confirmed but about whose interiors we can currently only theorize. It's absolutely absurd that we have several active rovers tootling around Mars and non on the Moon.

This argument that 'we went there already, there no reason to go back' just demonstrates a lack of imagination, at best.

Putting people on the moon today is like that friend who won't stop talking about how we was on the football team in senior year and they went to the state championship.

No, that'd be talking about how much we achieved with the moon landings while doing little else since.