LJ, you illustrate entirely why RAF Cabin Crew should be aircrew and wear an appropriate Brevet. You see them as airborne waiters, the various appellations that you list underline to you your view of them. What would you have them called then? The Emergency Response Team? Airlines or Air Forces alike don't wish to over egg the possible emergencies that pax might be confronted with, so a familiar emergency brief (so familiar that many ignore it), a mention of the seat back emergency information sheet, and that's it.
It isn't for the Cabin Crew. They must be prepared on every take off for an Abandon at V1 followed by the safe rapid evacuation of all pax. They must expect to deal with Toilet Fires (infamous for rapidly spreading smoke and lethal fumes if someone has dropped their illicit butt into the waste bin there). They must know what to do if there is a loud bang, the cabin fogs out, and the ubiquitous rubber jungle appears. They must know what to do in a hundred other such scenarios in the midst of dolling out meals, drinks, landing cards, whatever. In other words they have to be properly trained for their primary role of saving lives. They also need to know all about the routine stuff of course, and how all that can be learned in 3 weeks is a puzzle. I can only suppose it to be a very intense course!
Many civvie pax also see airline cabin crew as simply there to wait upon them, it is true. But they have the excuse that they are not aircrew themselves. Aircrew should know better and I sincerely trust that your attitude is the exception rather than the RAF norm, fella.