Well just because secure parts of the airport are not guarded or closed off, is not the crews fault now is it?
I am not CC, I am a Pilot, in our CAM (Cabin Attendant Manual), it quite clearly states that the checking of boarding passes is a security check, the last one. Also there is the case of Hand Luggage, Unruly passengers, Animals in the cabin.
No hold on, you know it all and therefore are not prepared to listen to anyone inside the industry who does this day in day out as you know better. Sorry to have bothered you Sir, would you like to tell me how to fly better?