Why would a life-time civil servant withold information from the UN?

US officials were outraged that Hans Blix, the chief UN weapons inspector, did not inform the Security Council about the drone, or remotely piloted vehicle, in his oral presentation to Foreign Ministers and tried to bury it in a 173-page single-spaced report distributed later in the day. The omission raised serious questions about Dr Blix’s objectivity.

And

The report says there is “credible information” indicating that 21,000 litres of biological warfare agent, including some 10,000 litres of anthrax, was stored in bulk at locations around the country during the war and was never destroyed.

Interesting. Now read the headline in the Inquirer this morning as well as the first paragraph.

The United States and Britain, undeterred by largely upbeat reports yesterday from U.N. weapons inspectors, asked the Security Council to impose a firm deadline on Iraq's Saddam Hussein, giving him 10 more days to fully disarm or face war

If 10,000 liters of anthrax is upbeat, what would constitute grave?