How Do You Make Stupid People Actually Safe?

In the wake of the Batman shootings, the AMC theater chain passed a ban: no patrons would be allowed to attend in costumes that obscured their face.  In addition, no fake weapons would be allowed into the theater.
A moment’s thought would make you realize how foolish this is.
For one thing, “covering his face” wasn’t the problem: afterwards, he went and waited for the cops to come and get him.  If guns don’t kill people, face paint certainly doesn’t.  There’s the slight danger of maybe it’d take the cops longer to find the shooter if he’d worn a mask, but chances are that they’d have tracked him down anyway. And any good bank robber knows that if concealing your identity is a concern, you can just stuff a ski mask into your pocket and put it on before opening fire.
Then there’s the weapons ban, which is completely useless.  The actual shooter, so it’s said, entered through a propped-open exit door.  Even before the ban, the shooter realized that hauling in an armory on his back would have raised questions, so he sidestepped the existing personnel.  Post-ban, it means nothing, as I highly doubt the rent-a-cop security guards at the theater would be a serious deterrent to a murderous terrorist.
So why have these bans at all?  They won’t stop any prospective shooters, and they punish enthusiastic fans who like cosplay.
The answer is easy enough: because those things would make customers nervous. But those people are stupid.  Yes, these bans will make them feel better, but in reality they’re not one iota safer due to the stoppages.  I mean, if AMC had said, “We’re having all of our theaters hire emergency security to police our doorways,” then that would be an effective security procedure… But they didn’t do that.
They encouraged the ostrich route: Can’t see any people in masks?  Then you’re safe!  And yes, that makes people more likely to pony up at the box office, but it’s security theater: if a maniac wants to kill them, that maniac will not be significantly deterred.
So how do you fix that?  In a sense, it’s not the theater’s problem, because you know, hey, this is what the people want.  But what do you do when what the people want is stupid and shallow and not a real solution at all?  How do you train people that no, this thing that terrifies you isn’t what will harm you, and this thing that you could give two shits about would actually keep you safe, if you dared to actually do it?
Because I guarantee you, AMC did the “smart” thing.  They could have hired a ton of extra security, for a negligible risk of copycat killers, and still had people freak out over the guy in the Joker costume.  The extra security would be mostly non-visible, and the guy in the costume would have caused some people to ask for their money back.  So that’s the smart money, doing the thing that does nothing at all.
Yet in the end, feeding those stupid instincts gets us hollow exercises like the TSA – look at how incompetent they are! – where we figure, “Hey, we’re inconvenienced sufficiently, this must be good stuff!”  Meanwhile, we’re always one threat behind, searching shoes and making travel so hellish that people don’t want to do it unless they have to.
So how, if ever, can you educate people as to what a real threat?  Can you?  Or are we forever going to be stopping Batman and letting the Joker slip in through the back door?