Why can you safely assume that? They've already released videos they couldn't explain which had very easy explanations. The US military isn't in the UFO debunking business. They're in the blowing things up business.
And second, from my own personal experience working in this area. We saw anomalous stuff on visuals/FLIR all the time. When you start seeing stuff on visuals/FLIR and radar/lidar/sonar/etc systems, then it's definitely worth a decent look.
The military is not into scientific rigor as much as it is into blowing things up and supporting contractors while chasing/developing tech.
We are conveniently in arms races with: China, Russia, etc.. and starting a most likely terrible election cycle with lots of new tech to be used.
It follows that UAP concerns can easily pivot into “enemy tech” arms races, when necessary.
If that does turn out to be true it’s a major turning point in world history as the US discovers they are now are no longer the most powerful airforce in the world and has some very real and very serious knock on effects that come with it.