Do you not see the irony? If it's not your responsibility, why should it be the responsibility of the author of this tutorial?

People write tutorials on what they are interested in, what they have knowledge of, and what they want to share.

Accessibility is an important topic, to be sure, and is clearly of particularly high importance to you. Others might complain that they didn't include how to create a high performance table view, or embed an OpenGL view. I think most people, however, will take it as what it is - a well written, helpful contribution.

Your comment specifically asked if you were being harsh, and the consensus appears to be "yes". Perhaps if you worded things differently you might get a different response.