Grips are not interchangeable with p.a.'s

I see this all the time. Someone trying to get into the film business as either a " p.a. or grip". Implying that both are interchangeable as entry level positions. I also see definitions of grip as "carries things", or "moves things." What the hell is this? For all you unedumacated, here it is: Grips are in charge of bounced and diffused light, shading, moving camera, specialized lighting and camera rigging. We also move set walls for shooting if need be. To be an effective grip you have to know lighting, basic engineering concepts, safety, lenses, moving camera platforms, basic construction. These guys spend years learning all of the aspects of the job. They hang thousands of pounds of truss over actors heads, rig and mount cameras on cars, boats, planes, bridges, and anywhere else the director wants it, shade and diffuse lights to meet the demands of the DP. If no one knows how to do it, they go to the Key Grip. With his/her army of grips they'll figure out how to do it quickly and safely. This is not to disparage my p.a. friends,which is an entry level position for the DGA. I'm just tired of being classified as "unskilled labor" by some jagoff who doesn't know any better.