What's the shame all about?

In reply to Tracy's previous post, our old buddy and frequent commenter Ryan wrote:

Man am I sick of L.Miller explaining how she's doing the world a favor by reading stuff.

Where does this attitude come from? With reading and writing many people seem very very anxious that either activity might be a filthy, selfish act--moreso than I've ever observed w/ other recreational activities. I've never seen someone ask this about watching TV, playing cards, snow-skiing, running a marathon, etc. But with reading or writing the debate seems to always be limited to two main choices: either reading/writing is a) a selfless act that we willingly submit ourselves to for the betterment of society, or, b) a nasty selfish masturbatory act that we should be deeply ashamed of. It's really weird! 

It is as if we always need a very good reason to be reading or writing, whereas other activities are taken at face-value as recreation. Even when talking with Prof Forhan here at Butler--who is a tremendous professor of poetry! as well as one of the people most responsible for my love for it--I noticed that discussions of poetry are usually prefaced by some mention of its supposed utility. In the case I'm thinking of he claimed that it could "save your soul"--which, you know, might be true. But if he were a mathematics professor and I had gone to him to share my deep interest in number theory, I doubt he would have felt the social pressure to say anything about the practical benefits of number theory; we probably would have just got right down to business!

I've noticed this tendency too, and I don't know how to explain it. Partly it seems to have to do with the  tendency among liberals and academics alike toward infuriating purity contests, but I think it goes deeper than that -- not all readers are, after all, liberal academics.

It's strange because reading and writing alike can be pretty excellent social capital. If you're weird about it -- the sort of person who expects everyone to care a lot about your writing, ideas about writing, etc. purely because you write -- that's like the worst thing in the world, and yes, a lot of people are honestly really weird about it. But generally writing and reading alike signify education, intellect, thoughtfulness, even morality and money. So why do we get so hung up about it? Why the defensiveness?