http://dictionary.reference.com/browse/read
The relevant definition of "read" is "to look at carefully so as to understand the meaning of (something written, printed, etc.): to read a book; to read music."
You look at the words and comprehend the meaning. That's reading. Reading, like any other action has a context, but that doesn't make that context an actual part of reading. That's the mistake the author is making, he assumes that the context in which he prefers to read is an inherent part of reading, and that without it, it isn't reading.
Boxing isn't just punching people, for example, the context - in the ring, in a boxing match - is an inherent part of what makes it boxing. Remove that context, and it isn't boxing, it is just fighting. But with reading, you can change that context to your heart's content, and it's still reading - the context is not part of what makes it reading.