Personally, I do feel it's kinda unfair. Once you leave school/ uni employers need to be able to judge you academic skills based on your grades - how can they trust them if you got 25% more time to do the exam??? Plus, they can't ask whether you have a disability of not due to discrimination laws so they have no way if knowing.
A fairer way would be to allow job applicants to state whether they have a disability that could have affected their grades and let the employed judge whether they can do the job.
I have friends who get extra time for silly things like writing to slowly or being 'slow processors'. While I recognise that some people have a genuine disability, being a bit stupid isn't one of them.
Sorry if this is rather a controversial opinion, but it's frustrating seeing all those people diagnosed is ohony disabilities or who faked the tests getting an unfair advantage in their exams. Not telling employers that they have this 'disability' is then tantamount to lying about abilities they do not actually have.