Which is why I think a guest affected by the change should request an exception from Universal followed by ADA complaint.
The reason they give might satisfy you. It might be enough to get an ADA change.
It might be corporate double speak.
I don't know if any of the posters are in that category.
I'll continue to speculate emergency unload not at a load unload zone normally used might be a reason.
Posters aren't going to get real information on internet discussion forumss
I just went to WDW prior to foot surgery and have been to other amusement parks with an ECV and in a boot or knee brace. I also have a couple of non-visible disabilities and have had both work and school accommodations, so I'm fairly well versed in the ADA.
WDW is FANTASTIC with mobility disabilities. At the time, I could walk a few steps, but basically anything I needed, they could accommodate. The only ride I really couldn't do was PeopleMover because you have to be able to walk up the moving ramp*. ToT...if you can't walk, you can get right up to the seating area. RnRC...third row has a car with a door and a handrail. I made use of this because it was MUCH easier in a boot. They have you board from the exit, and it allows extra time. Most of the other rollercoasters have a car with a door as well, as does ROTR. I did not need this, but it was available. The only attraction where they asked specifically if I could do stairs was Tiana's. In an emergency, yes, I could have. I think they would have flagged where you were if you said no and made alternative arrangements, but I am not 100% sure. When I got to the entrances, any attractions where I had to transfer, they made sure that I could before I even got in line.
Now for other parks:
It is VERY common for a park to deny boarding if you are wearing a prosthetic device on a rollercoaster or if you are wearing a hard cast. Some rollercoasters also specify guidelines for if you have a missing limb, such as "you may still ride if the limb is below this point." The ability to grasp with both hands is also a very common rider requirement.
Hersheypark and Busch Gardens Williamsburg, which are the two I've been to while using an ECV/mobility impaired, don't seem to be nearly as mobility friendly as Universal is (Universal overall is a very disability-friendly park IMO, though there are still ways I think they can improve). You can board from the exit, but that's it. They also have restrictions on hard casts and prosthetic limbs. Several of their more intense rollercoasters also have requirements that you be able to fully grasp.
The unfortunate reality of when you are disabled is that you accept that there are some things you flat out will not be doing because there's no reasonable way to make it work for you. Make no mistake: if there is a way to make things accessible, I will always advocate for that because we can always do better. Key word, though: reasonable. If something is unsafe and there's no reasonable way to make it safe for a disabled person, then that disabled person can't do that. For context, dwarfism is a disability under the ADA. I've never heard of anyone with dwarfism making a stink because they can't ride a rollercoaster when they don't meet the height requirement.
Because of my disabilities, there are certain attractions at Universal I know will make me sick. Not in a "this will kill me" type way, but in a "I won't feel good for the rest of the day" type of way. Yeah, it sucks. Those rides also aren't inherently unsafe just because they would make me feel unwell. Same with rollercoasters. People have conditions that would make them not feel well after riding. Doesn't make them not safe.
*Most newer buildings are required to meet requirements set out by the ADA to be mobility accessible. PeopleMover came before the ADA and is not part of this requirement. I hope that some day Disney does a thorough renovation on that ride and makes it accessible, but if that was the only ride I couldn't do? Thrilled.