The rationale behind it isn't inherently suspect but the way it's being conducted. Right now it seems far that security personnell are beind distracted from noticing potential threats by making them overly preoccupied with the purging of questionably liquid items such as chapstick and toothpaste in the name of fighting terrorism. Just like the urgent run on duct tape, the ban on anything remotely liquid seem to flow from the "Just Do SOMETHING" theory, which is a central tenent of the Reject All Common Sense School of Public Safety.
If we are so concered about airport security what about all the tons of unregulated, unscreened cargo in the belly of passenger planes? Or the failed tests conducted by federal investigators where bomb making equiptment got on planes undetected in 21 airports? Or what about the fact that just this summer the Bush Administration tried to cut $6 million dollars in bomb detecting funds from the DHS budget?
Nah, let's not talk about any of that when lip gloss and moisturizer are clearly a much bigger threat.