Enlisted are allowed to bitch.......Officers are not....
From the UCMJ (uniform code of military justice for all you civvie types)
888. ART. 88. CONTEMPT TOWARD OFFICIALS
Any commissioned officer who uses contemptuous words against the President, the Vice President, Congress, the Secretary of Defense, the Secretary of a military department, the Secretary of Transportation, or the Governor or legislature of any State, Territory, Commonwealth, or possession in which he is on duty or present shall be punished as a court-martial may direct.
http://www.au.af.mil/au/awc/awcgate/ucmj2.....htm#SUBCHAPTER X. PUNITIVE ARTICLES