How does this "bottleneck" prevent someone at the back from pulling a semi-automatic weapon from their stroller and using it to take out hundreds of guests who are trapped in the bottleneck? Is this what would be characterized as an acceptable risk?
In that the risk of this is very small and far outweighed by the advantages gained, yes.
I'm not trying to be glib, but your concern is just not well placed in this instance.
For instance:
I do think the bottleneck at security is an ideal terrorist situation. Once a gunman opens fire, the crowd would most likely start stampeding, so there would be even more victims. Look at what happened at Disney Springs last Christmas.
Pull up magic kingdom sattelite view on Google maps. Look at the entrance area. Big wide open area. No one is confined until theyes get under the roof for bag check. If something were to happen at bag check there is ample room to run and even a bit of cover. Stampeders are dangerous when people are enclosed or restrained by barriers. That's not the case here.
On the other side of bag check there's a short but wide 'air-gap' then a narrower entrance to the park. If there's violence at bag check, this narrow opening can be closed off and defended. Allowing a gunman to get into the park would be catastrophic. If your worrying about 100 people in a mostly open courtyard panicking, imagine 400 people on IASW trying to get out at once. Or the nearly 100 peogle locked into soarin in each of the three theaters.
One can get manic considering relative threats like this. I would know. The more I learn, and what I've seen doing field work (remember the Mumbai massacre?) is enough to keep anyone awake at night (3:26 am on my clock).
So I ask you, if the bottleneck is an essential part of the security screening, couldn't it be created after everyone goes through the X-ray machines and bag check?
So speed up bag check then slow people down some other way in some other place? Sure, can be done. Looks like this... you speed through security and x-ray because theyes are going as fast as humanly possible. Then you are directed to one of several holding pens where you will wait with a cohort of fellow vacationers for 15 to 45 minutes before finally being released into the park. This is the model airline passengers are familiar with.
It's easy to overvalued the risk posed by something when the consequences are extreme, or when they have occurred in recent memory. It's a cognitive bias called the 'availability heuristic'.
But Disney's track record is superb, and that's because of, not despite, the security choices they've made.