Security lapse ? Probably not. Against company policy ? Most likely. It sounds like the lounge staff member knew she had bended the rules and became defensive trying to shut the OP up and not getting into trouble.
If the OP is not aware of security procedures and airside etc.. then I would not blame them for highlighting this. In the current threat level it is the duty of the public to be alert and speak out if they notice something they believe is not allowed or suspicious.