Some may consider the subject matter covered to be off the wall concepts loosely based on preconceived notion. Its important to remember that the topics, aside from a few on popular legends, are strictly based on physically existing evidence in both the form of objects large and small and cross-references in historical record. Physical evidence is then presented and left for the interpreter to decide how they feel about it, which is what makes a lot of these phenomena a mystery. Most of the subject matter including structures have only been researched to 5% of what archaeologists and scientists believe may exist. Very similar to sequencing the genome, only around 5% to has a known purpose as genes. The remaining 95% appears to be non-coding DNA junk, and as it were some think the non-coding DNA junk may have been added by some other means.
For either situation scientists can only work with the materials they have and speculate about the purpose of the rest until that too is uncovered. The research and study isn't contingent on events purposed to have happened or events speculated to might happen, its purely drawn from the physical evidence seen throughout the world. A lot of highly distracting paranoid conspiracy theory has been intermingled with the subject matter, probably because its a natural psychological reaction for mass populations. Until the fabricated ideas are separated from the actual facts, perceptions will remain as they are. Earth has a rich trove of ancient history that cannot be denied and our ancestors deserve a little more credit than the primitive labels stuck on them.