"Once you do put security measures in place, the one thing you must avoid doing is weakening them."
The point is that no-one is suggesting weakening the procedures. We are suggesting that the security procedures are not strong, are wrong.
You are suggesting that people will imitate pilots to get airside, but as I pointed out they can do less damage, realistically, than they could in Tesco, but since they are surounded by security-minded professionals, rather than dazed shoppers, and they are expected to behave in a very specific way, they are far more likely to be caught. What do you think it is like airside? Do you think that there are crowds of random people walking round the aprons and taxiways alone?