I mean, its trivial to prove something isn’t Bigfoot on the grounds that Bigfoot Isn’t Real. That’s just Hitchens’s Razor. The burden of proof is on the person presenting the claim, not the one refuting it.
Shifting the burden of proof doesn’t disprove the claim. You can look at a picture and call someone an idiot for believing it’s bigfoot/a drone, but still not be able to swear that there is no way it could possibly be a drone.
Exactly. The military isn’t obligated to look at every single picture and tell you that it’s not a drone. But if they don’t do that, they can’t say “we have looked at every single picture and confirmed there are no suspicious drones”.
The military is rightly refusing to prove a negative.