I think that would all depend on how advanced this hypothetical tech is, and the timeframe in which someone wants it known to the public. DARPA may not provide enough cover for sufficiently advanced discoveries that cannot be explained without raising bigger questions.
It could also be a misinformation campaign meant for adversaries to make it appear that these hypothetical discoveries are backed by a source that may potentially yield more.
Beyond this, perhaps we now have evidence that adversaries reverse engineering the same tech are ahead of us, and enlisting the broader scientific community is now the primary goal.
And again, I’m not saying these are likely explanations. But in the unlikely event that we’re really talking about alien tech, they seem plausible.
There is also that fermi paradox resolution that basically says the same tech that unlocks infinite energy also unlocks the ability to destroy ourselves. So in theory there could be good reasons for avoiding commercialization of highly advanced technology, if it means that within a century some guy on the street could build an apparatus that destroys the planet in an industrial accident.
AI could unlock the ability to destroy ourselves and we've commercialized that highly advanced technology but it sure didn't stop the majority of people from wondering "should". :P
It could also be a misinformation campaign meant for adversaries to make it appear that these hypothetical discoveries are backed by a source that may potentially yield more.
Beyond this, perhaps we now have evidence that adversaries reverse engineering the same tech are ahead of us, and enlisting the broader scientific community is now the primary goal.
And again, I’m not saying these are likely explanations. But in the unlikely event that we’re really talking about alien tech, they seem plausible.