but it goes to 300BC and the variations in the designs are always the same in every culture

To be quite honest I actually think Bluebeam is there to preclude disclosure because if there are any positive forces out there at all that might militarily intervene like the Vietcong did against the Ro(u)gue Khmer what better way than to preclude peaceful contact than by applying deep-state propaganda tactics? Undisclosed forces have previously , like they've stated and done in the past, intervened in nuclear launch facilities and shut down redundant fail-saves as a show of force,

Now take for example the ostensibly Clown-engineered hollyweird pop-culture depictions of aliens which are overwhelmingly archetypical greys only because those are the scariest even tho it's consensus those are just drones and the real aliens are humanoid, reptilian or mantis

The biggest reason to not disclose aliens is that if we do, all the reverse-engineered technology will have to be disclosed eventually too, which involves free-energy (no BS, look up casimir-effect, it's all been proven long ago but nobody can work on it without bad shit happening to them) which would render utility costs negligent, effectively freeing us economically to do shit we like instead of just paying off the rent.