They do ignore accessibility in both content and the website design itself. It's frustrating to see all those websites that are trying to teach about design, or even offer design services, but with their own websites containing illegible texts, broken layouts, invalid markup, etc. Heck, even those that claim to aim accessibility and validity often fail to achieve any.
Just a few examples to demonstrate what I mean:
- Grey-on-white color scheme: high brightness, leading to eye strain.
- Font sizes and div widths are set in pixels.
- Fails validator.w3.org validation.
- Light-grey-on-white navigation links: low contrast, leading to barely legible text.