If they were anywhere close to evenly distributed across the US or the globe, one would expect plenty of eyewitness data from commercial airline passengers.
That this phenomenon appears specific to personnel and locations related to US military bases seems like an important piece of data.
There are some historical reports floating about from when the soviets and US were working together after WW2 or something and shared information on these events.
Radar and infrared aren't infallible. The story of the pilot who saw something with his own peepers has my attention but I don't trust what they've only "seen" on instruments.
What mint? A drone? A balloon? These are relatively common for surveillance devices and can be quite small and can self destruct. Even the US does this, just isn't as flashy.
My guess is if there was aliens they would be so totally disinterested in us they wouldn’t even distinguish between military and civilian. Just zipping around taking their measurements of the mineral deposits.
You have nothing to back that up and your gut goes against the closest thing we have to evidence...
If I was an alien race sending probes far and wide I would absolutely focus my attention on hotspots of military presence rather than the relatively benign nature and civilian existence.
