Pentagon hackers

The astonishing thing about the revelation that an infected USB stick caused the US military to suffer its most serious hack is that only now does the Department of Defense admit it is getting serious about hacking.
In 2000, Rand consultant Bruce Berkowitz wrote in Foreign Affairs, “US defence experts have been as intrigued by the prospect of attacking an opponent’s computer networks as they have been worried that someone might attack their own. Officials recently began to talk openly about such offensives because several developments made the opportunities obvious and irresistible.”
Berkowitz’s article preceded the exploits of Gary McKinnon, the self-confessed British hacker whom the US now wants extradited for committing what was until now, “the greatest military hack of all time”. McKinnon says he was looking for evidence that the US was suppressing UFO technology.
McKinnon also says it was easy to hack Pentagon computers. Once one computer “trusted” you, the rest did too, he says.
The fact that in 2008 someone was able to use an unauthorised flash drive on a military computer almost beggars belief. The private sector has known for decades about the threat posed by memory devices, both for unauthorised copying of confidential information as well as a carrier of malware.
There are scores of applications and protocols that help companies mitigate such risks. Why were these not in force in a battle zone, where the consequences of ignoring such risks could be deadly?