It just won't do anything. And it's really obvious that it won't do anything.
Could they be covering something up? I can't say it's impossible.
I'm just saying that between the tendency towards overclassification, the UFO stigma, and seemingly legimitate counterintel concerns, it doesn't seem like this refusal is evidence of a cover-up in and of itself.
They have always "admitted to the existence of" things they can't identify in some videos, blurry photographs, radar tracks, etc. UAP doesn't mean aliens, it just means "I can't tell what this is." Most of these UAPs turn out to be shit like commercial airliners far away on the horizon, and they remain "unidentified" because nobody cares enough to actually figure out what they are.
And you take this to be suggestive of aliens? Please!
Anything else is speculation, one way or another, and that won't lead to a broad consensus.