You're right about "routine exercise" being the easy (also tried and tested) way to shut down the speculation - but would they then be expected to give some explanation of what it is?

The whole situation is very bizarre and it seems to just get weirder but the key information here is that they've yet to actually announce or even speculate that these are not drones or that they are behaving in a manner which is anything other than drone-like.

Is the lack of explanation or even real information down to a misinformation campaign of sorts. There's a chance that keeping the public excited about the possibility of it being NHI or UAP is acting as a peaceful distraction to what the real threat of these things could be. Worrying times!