The military are not governent officers like ambassadors, I don't even understand why you are reading it the way you are reading it.
But the commissioned officers are "officers of the United States."
http://caselaw.findlaw.com/data/constitution/article02/
I think I am reading it the way the Legislative, Judicial and Executive branches of our government read it.
See:
http://caselaw.lp.findlaw.com/data/constitution/article02/13.html
Here is the actual US Code that the Constitution backs up:
http://www4.law.cornell.edu/uscode/html/uscode10/usc_sup_01_10_10_A_20_II_30_33.html
http://www4.law.cornell.edu/uscode/html/uscode10/usc_sec_10_00000741----000-.html