I don’t disagree with everything you said but, a legitimate concern is some lone wolf who has little to no training from an organization going out and committing a mass shooting. They may be inspired by an organization but not necessarily part of their group.
Metal detectors are far from perfect but they could potentially stop someone in this lone wolf scenario. That is why single males seem to be the focus of the profiling (and yes that is wrong of them to profile.) Yes, of course they could open fire outside the gates just as easily and the news reports would say at Disneyland, but a mass shooting on Main St. USA would have a devastating effect Disney’s business. That is what they are trying to prevent. This isn’t aimed at some coordinated attack by an organized terror cell.
This has been terribly mismanaged by Disney however.