Dude, the guy I quoted said this still puzzles engineers today. That's just the unfortunate marketing part of archeology.
What I said is that no it does not puzzle engineers today at all.
Then you replied saying hey till today we have no idea EXACTLY how they were built and there's no proof of the most plausible theory.
Those are two different things, and I think it's important to make the distinction.
1) How the pyramids were built does NOT puzzle engineers today
2) There are many theories as to how they were built but there is no proof allowing us to be 100% sure how they were built.
So we dont know exactly how they were built
but we know humans could have done it with massive amounts of labor in different ways, we don't know which one yet.
But we may never know, however that's another story,
but my point is we know enough to know there's no mysticism here or a need of alien involvement.
So there are theories as to how it was done, but we don't have proof of any of them.
But we don't know which one not because it's puzzling but only because there's no proof.
This seems to be an important distinction that needs to be made in this thread from reading comments.
Check this
How Much Would It Cost to Build the Great Pyramid Today? | Live Science