There's nothing secret about that. It's a satellite and it's for the NRO. What's secret is what it does, and what its orbit will be. (Once it gets to its final orbit, I guess there are amateur satellite trackers that will figure it out, but not until then).

The webcast host may not (I'd guess he probably doesn't) know what the satellite does or its final orbit. He does mechanical design. I'd bet they keep that information compartmentalized within SpaceX so only the operations personnel who need to know would know.