I wouldn't call it much of a disinformation "campaign", just fantastical lies they are trying to sell. Like a few years ago when Tom Delonge ended up doing those UFO panels with "intelligence insiders from the highest level". They look like con artists.
Back to the link above this David Grusch, let's assume he is telling the truth that he saw these things. First his story makes him sound like a discount Bob Lazar. Yeah, we've heard this before 30 years ago, the government has "alien craft" in their possession, more than one variant, some fully intact. He's pretty much copying Bob Lazar. I personally don't entirely discredit Bob Lazar, he may have actually seen this.
I'm not entirely denying the U.S. military has craft in their possession that would look alien to most people. I believe they do. If it is true, these craft are not of alien origin outside of earth. It's far more likely they are from ancient terrestrial origin, unearthed from a past advanced civilization.