That's a fancy way of saying that people are offended by discussion of the idea. And again... BRITISH sites are just as much a part of the Ancient Aliens idiocy as everything else. For example:
https://en.wikipedia.org/wiki/Stonehenge
It's the same basic question as most other megalithic sites. In fact this is where it got started. Multi-ton stone blocks stacked like dominoes. Who? how? Well it was built probably around 5000 years ago by a people who left no writing. We don't even know if it the descendants of the builders are still alive.
https://en.wikipedia.org/wiki/Cerne_Abbas_Giant
No one actually knows who made it, when, or why. And like the Nazca petroglyphs it's largely impossible to look at on foot. There is some reason to believe it was made in the 17th century though.
https://en.wikipedia.org/wiki/Temple_of_Jupiter_(Roman_Heliopolis)
Yes that's right, one of them is a Roman temple! 800 ton stone slabs moved to a hilltop for foundation blocks!!!
So the idea that the AA movement is racially motived is unsupported by evidence.
Von Danniken used the Temple of Jupiter as one of the examples in his book. He didn't write the book to mock non-white people. He hit everyone equally. So while I think his book is nothing but amusing fiction, I don't see it as racist.