The FAA has 45,000 employees. Not all of them work with airplanes or aviation safety. They have janitors, secretaries, IT people, groundskeepers, etc. Not all of them need to be able to pass a flight physical.
They are recruiting for general personnel needs, not looking to put mentally ill, or blind people in cockpits/flight decks. But there's no problem with someone in a wheelchair being a computer tech...
I will acknowledge I had the same thoughts as everyone else when I first saw this. I'm a retired US Army Civil Servant, so I have a bit of insight into the hiring of "persons with disabilities."