Perhaps don't make assumptions. Not that I owe you or any other "expert" speaking out in this thread an explanation, but I hurt my shoulder a few months back and extending my left arm up even a little bit is still excruciatingly painful, and that pain lasts quite a while after making said motion. If something *I* do sets off the metal detector, that's on me, but if a stupid, poorly planned policy of forcing me to carry metal objects that I know for a fact will set it off is what's going to cause me physical pain, you're damn right that I'm going to speak out against it.
So big deal? Yes, it is a big deal. Like everyone here, I'm a huge supporter of the Disney product - but that doesn't mean that I - or any of us - need to just blindly support everything they do, because some of those things ARE poor decisions that negatively impact guests "Because The Rules."