Same reason the feds didn't say anything about the F-117 in the 80s when hundreds of people in nevada were mistaking it for a UFO: They have no interest in telling the world about the exact nature of their ISR assets.

The US DoD has recognized a lack of capacity and capability in our native drone programs when examined in context of the Ukraine war. They are spending plenty of money to shore of that lack, and not all of the programs and projects they are funding are through Anduril and have literal fan groups.