The buzzing at the door is so the person can come to the office where the identification takes place. If it is necessary for the ID to be pulled out and verified with the paperwork, the ID will be handed to the office person in the office and not at the door.
The door is not for identification. It is to prevent unhindered and direct access - so that no one passes through that door without the office knowing. That’s the first “line of defense” so that if anyone goes past the office without being identified in the office - then the police can be called immediately and that gives the police the advantage of precious minutes to apprehend someone who has not been identified.
The moment you permit someone entry into the building without identifying them, you undermine your own security.
Sadly, the idiocy of not identifying someone before permitting them access will almost certainly continue to be practiced (and be defended) until tragedy strikes and someone who is buzzed in reveals his or her criminal intent—with tragic consequences.