The point is that ultimately, we are trying to deliver content here. Yes, its important to be able to navigate the site structure efficiently in order to find the content we are looking for, but if that content is by its nature inaccessible, then what have we accomploshed?

I am not sure the standards advocate bashing is fair. No doubt there are purists out there, but most do not tend to say validation is end all.

Most do, from what I can see, say that validation and standards compliant are very important. But, as you have noted, semantics can be poor even in valid documents.

I think most standards evangelists do recognize that. My understanding from reading a number of major evangelists is that they

1) preach standards as the starting point;

2) emphasize semantically meaningful markup as critical for accessibility, and

3) additional accessibility considerations are needed on top of valid markup and good semantic tag choice (such as good content).