Those groups don't have potential inflight access to the flight deck
Well, flight crews do, and thus have no need to smuggle a weapon that could be used to gain access to the flight deck. A ramper, mechanic, fueler, provisioner, cleaner, gate agent etc. would need some way to breach the door. Heck, it's HAPPENED, and yet, they are not searched for said weapons on a regular basis.
A pilot doesn't need to smuggle a weapon through passenger screening to take over the airplane, since that, by definition, is precisely what he/she does. We are either trusted, or we aren't. If we aren't then why the hell are we given complete control of a potential WMD. If we are, then why are we subject to the Greatest Security Show on Earth?
If FAs aren't trusted enough to use KCM, then they shouldn't have access to the cockpit in flight, since they have access to potential weapons in flight. The crash axe, portable fire extinguishers, POBs, coffee pots etc that are already on every airplane and can be used as weapons by pilots and FAs alike......