I recognize that you're posing a (presumably rhetorical) philosophical question, but it seems worth pointing out that there are certain contexts where accessibility is a matter of law.
If your content is intended for use or distribution by a US federal agency, or was created using federal dollars or as part of a federal contract, you are responsible for ensuring that it is compliant with section 508 of the Rehabilitation Act of 1973, which specifies that your content be accessible to individuals with disabilities.
Leaving aside for a moment the larger question of whether specific blind and/or deaf individuals consider their sight/hearing status to be a disability or not, section 508 is generally interpreted to mean that your content needs to be as accessible as you can make it. That means (among other things) working to make sure that screen readers and other such software are able to make full use of your site's functionality.
In my experience, the process of getting a project compliant with section 508 is generally very valuable- it makes you think a lot about how your content is organized, and rewards use of semantic markup. It can be frustrating at times, but the end result is definitely worth it for a wide range of reasons.
Here are a couple of places to get started learning about 508 issues:
If your content is intended for use or distribution by a US federal agency, or was created using federal dollars or as part of a federal contract, you are responsible for ensuring that it is compliant with section 508 of the Rehabilitation Act of 1973, which specifies that your content be accessible to individuals with disabilities.
Leaving aside for a moment the larger question of whether specific blind and/or deaf individuals consider their sight/hearing status to be a disability or not, section 508 is generally interpreted to mean that your content needs to be as accessible as you can make it. That means (among other things) working to make sure that screen readers and other such software are able to make full use of your site's functionality.
In my experience, the process of getting a project compliant with section 508 is generally very valuable- it makes you think a lot about how your content is organized, and rewards use of semantic markup. It can be frustrating at times, but the end result is definitely worth it for a wide range of reasons.
Here are a couple of places to get started learning about 508 issues:
http://en.wikipedia.org/wiki/Section_508_Amendment_to_the_Re...
http://www.section508.gov/