Doesn't strike me as weird at all. Saying you shot some unidentified unmanned stuff out of the sky sends a much different message than saying you possibly shot an unidentified someone out of the sky.

Not wanting to disclose what it was isn't the same as being fine with any interpretation of what was done.

"well, technically we recovered an alien so it was 'unmanned' because there were no men onboard"...some defense department lawyer

Balloons are treated differently under the Chicago convention. There’s a little bit more leeway for balloons when it comes to overflights on sovereign territory.