This nonsense is utterly harmless, but the purpose here is to normalize the establishment crushing disagreeable dissent, or anything that conflicts with bureaucratic and establishment narratives.

Now, there is something to be said about some inventions. You're right, there are some technologies we don't really understand and can't replicate. "Persian Fire" ships were one of them, Roman Concrete was actually another that we've only recently discovered how to re-create. None of these were made by aliens. Ancient Pyramids had long been a custom in Egypt for thousands of years, and the ones at Giza are probably one of the most stellar building projects in human history. How you move the bricks is difficult, but it's not at all impossible with enough men and ingenuity. Same with Stonehenge.