Unfortunately, since the Disney sites specifically mention autism, I've seen reports that people on Reddit and other sites like that are giving advice to say their child has autism. Rudeness is never appropriate, but I'm sure the CMs have had a very challenging few days.
It's possible the hang up was a result of the CM trying to add the specialist to the call. I've done that myself at work when trying to add another person to an existing call.
I would suggest trying again after a few days when things settle down, especially since you were told the CM would bring in a specialist and didn't do that. I have read accounts of people who called back, re-explained their concerns with waiting in line and did get approved.
The generic tips they gave regarding waiting in line were actually part of a brochure Disney prepared in consultation with autism advocacy organizations. The brochure has actually been on the Disney website since
DAS was introduced in 2013. It was several clicks in on the websites and I'm sure many people never saw it. Now, it's front and center on the websites and is being brought up in calls for anyone with cognitive/developmental disabilities.