The left aint got a damned clue. They really don't care. In fact, they believe that if terrorists can be ignored or appeased, the terrorists will leave everyone alone. That's what got the U.S. in trouble on 9/11, Spain on 3/11 and Britain on 7/7.
Let me rephrase that.
The Left downplays ANY revealed threat BECAUSE it might be politically advantageous to Bush and Republicans. Therefore they must immediately begin politicizing it, desperately seeking some controversial thing that Bush/Blair DID do or DIDN'T do (it doesn't matter).
Appeasement may explain the thinking of the naive, pacifist left. But there are others on the left who have a Romanticist fascination with the Rebel. Muslim rejection and violence against Western culture fulfills these leftists' fantasies of rebellion. These are the types who wear Che Guevara T-shirts. There is always an admiration for anyone who revolts against the "system." Hence the secret admiration of Islamofascists.