Please. I for one am using the fragment hack to build a richer user experience on a widely available platform. The interactions I am building wouldn't be possible without it (or the HTML 5 pushState replaceState equivalents). Rendering my content on the client in JavaScript makes me a lot more productive, and the interactions I facilitate on my site would be impossible without it. The implementation choices of a single web site cannot "break the web". I trust that the author of this post has a lot of experience and also valuable things to say about building accessible sites, but accessibility and graceful degradation aren't the only god in my pantheon.