Like Stonehenge and Easter Island, what if there are beings on the Moon puzzling about who left all that human space debris there?

They are pissed.   All they wanted were a few Playboy Magazines.  Maybe a Hustler or two.

they'll be wondering that for a long tinne

Nah, they would need s lot of luck to find the few footprints and stuff we left up there, But when the try to insert into a Low Earth Orbit they will wonder about all the junk we have put up there.