Yes, your interpretation of simple installation of metal detectors as "paranoia over nothing" and "will hurt its profits because they have basically said to tourists Disney is not safe" is bizarre to me.
Folks, if a measure "won't stop everything" that doesn't mean it "does nothing" or is "an illusion" or doesn't make us safer. It's about degrees of security. Of course it makes us safer. Nothing will make us 100% safe. That doesn't mean we should be careless about it.
Speed limits don't stop everyone from speeding. Speeders kill people every year. Cops can't pull everyone over. I guess we should just do away with speed limits. Plus, they impede my trip to Orlando and I just don't like them and they restrict my freedom.
But again, the thing that sticks out to me the most is competing parks all did the same thing at the same time. There is something behind that coordination.
Will it hurt Disney profits? That's silly.