Rule of thumb with conspiracies: the more people that would have to be "in the know", the less likely it is to be true.
This kind of story would require a ludicrous amount of people to be in the know. And each and every one of them would be a potential leaker, providing evidence to the public. And yet, somehow, the people who claim to be such whistleblowers never provide evidence.
Where is that alien tech? Can you show us any? Failing that, can you say where they're keeping the recovered space ships? If not that, do you have any of the actual documentation that you claim exists regarding thse secret programmes?
Nope. None of it. Every single time, it's just the claim, and none of the proof.
As conspiracies go, it's somewhat less unbelievable than the flat earth bullshit, but that's a low bar to clear. Without evidence, all of this is extremely unlikely.
(Not to mention the fact that we have a very, very well-documented overview of how all sorts of technologies were gradually developed. There are no mysterious gaps in this record. The idea that various modern innovations were secretly reverse-engineered from alien tech -- which is claimed in this article -- is just silly. It's the same bullshit as "aliens built the pyramids". No. Humans did that. We know how they did it, too. And in the same way, humans also invented the television. No alien assistance needed.)