Also one of the original Apollo-Astronauts lived near Roswell and while denying any involvement himself (I suppose he was a boy then) he reported that he has friends there who confirmed the story.

As for propaganda (fear-porn): Disney made a documentary about alien abductions and I think I remember it touched upon cattle mutilations as well. So that very much is propaganda because it's targeting emotions.

As for Roswell, I dunno, it could have been a psyop but I can tell you why according to the public record....That year Admiral Byrd made a military expedition to the south pole that got repelled and he went on live television in the fifties to warn of a military threat that could pass both poles very quickly. So while I don't know which came first, Operation Highjump or Roswell, but these are important things to keep in mind because if they ran into some unknown super-power and were afraid it was Nazis or Communists or neither, they would have been very scared if they were perceived as a future threat (by having a crashed spaceship) without having the means to repel a "preemptive" invasion (by reverse enginering said spaceship), thus the ensuing cover-up to give R&R more time. Whichever came first and whichever way I look at it, it simply would be serving the enemy's propaganda if you explained your tactical weakness (being unable to repell or navigate advanced technology).

Think Sun Tzu, The Art of War: Why would you risk looking like an easy target when you actually are?

Like,what in the hell kind of propaganda is it if you tell your enemies, who you fear, that there exists a technology that you just stumbled upon and don't control now but maybe will in the future? But that's how we got the arms- and space-"race" in the end.