It shouldn't come as a surprise that the US government looked into the US government's response and determined that the US government is doing a great job. They've given conflicting messages on this, including in briefings to senators, and Kirby got raked over the coals later in this briefing. And if you listen to his response, his denial is pretty carefully and narrowly worded - e.g., "many" have been identified as aircraft (how many is "many"? the majority? how many have you not been able to identify?) and we haven't corroborated any "visual" sightings of "drones" (have they been corroborated in other ways?).
All the lawmakers getting briefings on this seem to be awfully concerned, including Corey Booker, who is a serious person. Of course some people are misidentifying things and the concept of a "mothership" seems absurd, but it seems beyond doubt that *something* is going on and invading our airspace for a month and we haven't been able to do a single thing about it.