Interesting. You call it playing a security card, while the airline industry instituted it after 9-11 because the terrorists quickly gained control of those flights. All gaining access to the cockpits. GRANTED, the doors are re-enforced now. But, pilots do come and go from the cockpit.

Secondly, by the way you word your accusation, you blame the flight attendants for enforcing what YOU perceive as a no security issue.

Apparently you arent aware that the TSA instructed the industry to enforce this policy: http://online.wsj.com/article/SB108552796651521354.html

The Transportation Security Administration told airlines in December to police gatherings of passengers on planes for possible security risks, especially near cockpit doors. Since then, different airlines have interpreted that recommendation differently. And frequent travelers say airline crews often unilaterally go further these days, even outright barring passengers from standing in the aisles and the galleys in the back of the plane.

(another case of we dont make the rules, but we're required to enforce them)