I believe as a society we need to be more flexible in every area for every human and also to give individual attention to everyone so they can excel. Some people will need more help than others, like those with ADHD, and some will need much, much more help than others, such as those with more extreme sensory issues with Autism who may not even be able to go out in public without accommodations.
The world right now doesn't do a great job of "by default" accommodating people with the broad class of difficulties experienced by people that fall under the umbrella of neurodivergence and takes as given that everyone is in the 70-80% group. So now it's a disability with doctor's visits and paperwork and specific individual accommodations when it very well could not be.
I don't think a problem having a high frequency means that we should decide it doesn't matter or need rectification.
- is clearly defined
- can be measured objectively (with autorefractors, keratometers, corneal topographers)
- can be corrected cheaply ($20 glasses) to eliminate any disadvantage in performance or efficiency
Neurodivergence:
- is not clearly defined
- cannot be measured objectively, and is diagnosed using behavioral observations and cognitive tests
- may rely on 'accommodations' that, in the hands of someone without a diagnosis, would be considered cheating
Imagine I don't have astigmatism. If I were to take your glasses, would they improve my performance in college?
Imagine my legs are fine. If I were to take someone's wheelchair and start using it daily, would that improve my performance in college?
Imagine I am neurotypical. If I were to take 2x the time on a test, would my performance improve?
If you would find wearing noise blocking ear muffs, or sitting on a bouncy chair, or using a typing instrument instead of writing, improves your performance on a test, then yes that should be permitted.
(I do also think it would be a good idea if people had longer for many tests or tests had less on them. That kind of speed is rarely an important part of real world workplaces so those tests are rewarding low-value skills.)
The thing these examples have in common is that they don't give you any inherent advantage that invalidates the purpose of the test. (Assuming it's not a handwriting test, or an 'ignoring distractions' test.)
I would group all of these along with the examples I gave: corrective glasses, and wheelchairs. They should be available to all students, without diagnosis or discrimination.
If you think limited time on tests doesn't serve a useful purpose, then why give 'extra' time to only some students, and not to all students?