I may be wrong but I think the post you quoted is laughing at Heathblue's use of the word 'firmament' in the thread title - a biblical expression loved by anti-scientists but not by Terry Pratchett fans who know the world is balanced on the backs of four elephants standing on the back of a giant space turtle!
No idea why you think Elon Musk's alleged IQ is relevant to that - but it takes all sorts. (PS - He's not using his IQ much these days!)