You've missed the point. How does Stanford end up with 38% of their students claiming to have a disability while other schools only have 3%? Are the other schools illegally discrimating against these students, so that their only alternative is Stanford? Or is it possible that something anomalous is happening at Stanford?

While it doesn't explain the whole difference, it's not surprising that Stanford has a higher rate. First: the more demanding the environment the more likely you are to find (got example) milder ADHD to impact your life. Second: the more well off you are or more access to resources you have, the more likely you are to actually care to get diagnosed. Third: stressful environment can actually cause serious issues, suddenly. For non-education reasons I suddenly gained panic attacks while I was at uni and they took years to go away.

I'm sure there are more things like that.