This is not true, although the trend has headed in this direction over the last decade or so.

Several majors have been able to defend having their own, more rigorous, standards in court. Usually the pilot claims Americans with Disabilities Act (ADA) for things like wearing glasses and color vision. But the airlines have gotten those thrown out on the basis that the need to wear glasses or marginal color vision is NOT a disability...the definition of a disability is a condition which impairs everyday living, and wearing glasses does not count. If you had a bad leg and walk with a cane, the airline WOULD have to hire you per ADA, as long as you can hold a medical.

The good news is that many airlines seem to be tired of spending money on these lawsuits, so most arre getting more tolerant.