I will include an excerpt here assuming I have the a fair use to quote from the post:
If I create something copyrightable (and I'm a writer, so this is not just a gedanken experiment), I have the right to restrict who distributes copies of it. That is the only right I have under copyright law. I don't have the right to say 'blind people are not allowed to feed it through a screen reader.' I don't have the right to say 'you may not read this from a mobile device.' I don't even have the right to say 'you may not photocopy a few pages of this book to read on the train when you don't want to lug the entire book with you.' If you want to tear pages out of a book I've written, or change the font of something I've written for online distribution, then that is entirely up to you; I don't have the legal (or moral) right to tell you not to.
Copyright is a limited monopoly on distribution granted to encourage the production of content. It is not a right, and it is not a privilege; it is a trade. The state awards me limited rights in exchange for my relinquishing others (which I could retain by simply not publishing). We both win; I gain a method of producing income, while others gain access to the material I produce. By exercising copyright, I am agreeing to this; I am saying 'I wish to retain exclusive distribution rights, in exchange for publishing this work and permitting others to purchase it.' DRM alters this balance. If I publish a DRM'd version of something, then I am attempting to retain more control than copyright grants me. This is nothing more and nothing less than vigilanteism.