Why is a member of Congress commenting and not the DOD or the Governor of Montana? Is someone spilling classified information to show off?
Specifically with regards to Matt Rosendale, he is a Representative from Montana. He is in a position where he can demand (and will get, within reason) information from the US military and represent Montana in demanding and publicizing said information.
Congress performs oversight of the military and sets budgets, so they're briefed on operations like this which have some outsized political impact. It doesn't seem to me like these things should be a big deal but the rest of the people in the US seem to act like it is, so Congress is naturally very interested.
It’s all about making noise to stay alive - how often do you hear from congressmen from Montana?