It was glaringly obvious this launch had secret stuff on it.

Like a 2 year old trying to be sneaky while stealing cookies from the kitchen.

The one announced payload is rather lightweight. A Falcon 9 carrying so little weight will have plenty of reserve thrust to return to landing zone. The fact that they sent out the drone ship for this launch lets on that there was significantly more weight on board.

The second stage had a series of 3 burns announced. Basically it would raise its orbit to a certain intermediate height, sit there for a short time, and then raise itself all the way to the correct deploy height for the publicly acknowledged payload.

Unlike most SpaceX launches, there was no live video from the second stage in flight. They only do this when flying classified payloads. But this launch we suddenly got back second stage views after raising past the intermediate orbit.

All this is highly unusual so of course everyone is going to point their equipment at that orbital plane to try to find what got left there.

Trust me the defense agencies aren't pissed. They know it's impossible to hide any satellite, and that governments and amateur observers track everything. That's just the environment they have to operate in.