"No one ignored the hazards," Leon Panetta wrote in a letter published in the Washington Post, responding to those who questioned CIA tactics in eastern Afghanistan on a weekend during which some of the dead officers were laid to rest.
The revelations come hours after a tape was released in which the suicide bomber and double agent, Dr. Human Khalil al-Balawi, said he was motivated by revenge against the United States.
"This [suicide] attack will be the first of the revenge operations against the Americans and their drone teams outside the Pakistani borders," Al-Balawi said.
He added that he was avenging the death of Baitullah Mesud, the former head of the Pakistani Taliban.
The Jordanian doctor made his statement in English as he sat next to the leader of the Pakistani Taliban.
The CIA has been stung by accounts that suggested Al-Balawi was whisked past security checkpoints in Khost and was welcomed by a large group of U.S. agents. Panetta lashed out against such criticism.
"Public commentary [is] suggesting that those who gave their lives somehow brought it upon themselves because of 'poor tradecraft,'" he wrote. "That's like saying Marines who die in a firefight brought it upon themselves because they have poor war-fighting skills."
Panetta and U.S. sources added new details about the bombing at the CIA base. The double agent was driven past security checkpoints that the Taliban are thought to monitor and arrived inside the base. As he exited the car, his hand was in his pocket.
"The individual was about to be searched by our security officers -- a distance away from other intelligence personnel -- when he set off his explosives," said Panetta.
Some of those intelligence officers were 50 feet away, but still were hit by shrapnel.
But the criticism continues.
"You can't sacrifice basic tradecraft under pressure from headquarters," former CIA officer Frank McGovern told ABC News. "Here was a fellow who pretended to be tied in with the top al Qaeda leadership, so all kinds of shortcuts were made."
While unable to give specifics, Panetta said his agency has been successful against terrorists and will continue the fight.
"In the past year, we have done exceptionally heavy damage to al Qaeda and its associates. That's why the extremists hit back," Panetta wrote.
Family Mourns 'An American Hero'
As the debate waged, Americans got an extremely rare view -- the funerals for some of the country's silent, secret warriors.
In Bolton, Mass., hundreds gathered to remember Harold Brown Jr., a 37-year-old CIA officer and father of three young children. He told his parents he worked for the State Department.
Janet Brown spoke of her husband at services attended by members of the military and state officials.
"He was, by all accounts, an American hero," she said. "Harold Brown, it was a wonderful life. I love you now and forever. Thank you for choosing me."
When Brown's body and the bodies of the six others killed in the attack arrived at Dover Air Force Base Monday, the senior staff at CIA headquarters in Langley, Va., paused for a moment of silence.
Workers have been dropping off flowers at the headquarters' Wall of Honor. Ninety stars are carved in the wall. More will be added in the spring during an annual ceremony.
A separate memorial ceremony is expected soon at the spy agency's headquarters.
"There is a collective sense of loss at the agency when you lose seven," said Ted Gup, a journalism professor at Emerson University and the author of "The Book of Honor: The Secret Lives and Deaths of CIA Operatives." "That really sucks the wind out of the agency. They recognize the vulnerability that they all have. It's a high risk profession.
"Historically, the agency has provided letters of condolence to the grieving families and then withdrew them the moment after they were read and placed them in secured personnel files -- for fear that leaving the letters with the families would provide them evidence linking the casualties with the agency itself," said Gup.
The CIA said that practice is no longer used.
Panetta: 'We Do More Than Mourn'
Director Panetta offered condolences and a promise in his letter.
"We do more than mourn those taken from us," he wrote. "We honor them, in part by pushing forward the work they did, work to which they were absolutely devoted."