At the risk of sound like a crank, this book convinced me of quite a few things:
https://www.goodreads.com/en/book/show/750010.Witness_to_Ros...
The things I came away with were:
- Approx. 600 former USAAF (the precursor to the USAF) staff have admitted there was a cover-up of some description
- Multiple first-hand dying testimonies or "open after I die" testimonies agree there was a craft and several beings of unknown origin that were the subject of said cover-up
- Nobody with any expertise in Soviet technology believed it was within the capabilities of the Soviets.
- Nitinol possesses many of the qualities of the material said to be found by multiple eyewitnesses. It was actively researched only after this incident, and the public history of it doesn't tally with some documentary evidence.
And it's for those reasons I don't think anybody in the US military was prepared to just step back and accept that these strange objects were no threat or danger.
Nobody has to agree on ET origin to accept that something was found that posed a threat to the country, but most people do not accept a Soviet origin.
The Roswell incident showed to some that the US public were not ready for it. Highly religious people had breakdowns (they cycled in a new pastor on-base for that reason, as it happened), and some like the town Mayor really, really struggled to cope with what was going on.
So imagine you're briefed on all this as a top general in the US military. Wouldn't you put some money into trying to figure out what is going on, and to do so in a way that would not alarm Americans to the point of mass hysteria? Would you not want to throw some money at some covert operations to make sure you were getting a sense of what was going on?
As an aside, whilst the Roswell story has a fair bit of credibility - as many others do, it's just Roswell has more witnesses that have gone on the record - absolutely nothing that Bob Lazar has written stands up to an iota of scrutiny. That's not how security clearances work, period.