It's not just reading, but the greater expansion of a stereotype, and it's not just in today's society, there is a long history in which the educated or otherwise intellectually knowledgeable have been vilified, in both American society and the wider world. It's deeper than words such as 'nerd' and 'geek' being used as slurs in the playground.
Anti-intellectualism in the United States predates its national identity itself, and there is a long history within its education system in which there is little interest in developing children's minds, or for the pride of learning; but rather views its children as abiding citizens of a future 'democracy' to be trained. The 'No Child Left Behind Act' of 2001 was the final nail in the coffin following many decades of dumbing down the system, in which the teaching of critical thinking for today's children has been stolen from their innocent minds, and replaced with standardized drilling of information into their minds, it's now memorization memorization memorization.
Intellectuals became an oddity with the rise of McCarthyism, once highly respected they became targets of suspicion for Communist activities (itself becoming a slur for all Communist affiliations). The American public turned against intellectuals, distrusting them and turning them into scapegoats for income tax and the attack on Pearl Harbor. As Arthur Meier Schlesinger Jr stated at the time, 'anti-intellectualism is the antisemitism of the businessman'. With McCarthyism, banks, corporations, government became suspicious of Communist infiltrators. Education no longer counted for much in the workplace, nor did independent thinking. The new order was to become sheep, to stay in line and blend in with the general populace. President Eisenhower spread that distaste of intellects, speaking at a Republican meeting in Los Angeles in 1954 he stated; '... By the way, I heard a definition for an intellectual that I thought was very interesting, a man who takes more words than are necessary to tell more than he knows'.
With the passing of McCarthyism, the trend continued in society and of course remains today watered down in the beginning words I mentioned used as slurs. To be an intellect following McCarthyism, meant to be part of a privileged highly educated elite. Of course, to be an elite makes you open to not just anti-intellectualist attack, but the diatribe of the anti-elitists. It puts you out of touch with the Average Joe and the Plain Jane and upsets the social class, regardless of social background. The education system of the United States of America is failing drastically in today's society, as a result the United States has one of the worst education systems in the post-industrialized world and heavily relies on the foreign born coming to the United States to take up PhD's, with 55% of all PhD engineering graduates and 80% of all chemical & material engineering graduates being foreign born.
Unfortunately, there is a collective narcissism in society, and those outside our immediate social groups as a result are often perceived as strange or weird. This collective narcissism prevails in the school yard. Unfortunately the stereotype of the educated is oft linked with social isolation. This stereotype is enforced on anyone that doesn't meet the standardized needs to be one of the Average Joes.
The above however is part of a wider issue within society and politics itself. The United States doesn't do enough both socially and politically to promote education and educated intellectual pursuits such as reading. Instead the government as aforementioned, ruined the education system for memorization.
It is deeply regrettable that society has a deeper love and respect for the likes of the Hilton's and the Kardashians amongst us, rather than the Higgs, Hawking's, Hansen's or Dawkings. Arguably most children now dream of becoming celebutante's and leading jet set lifestyles with little or no work, than becoming a doctor, teacher, scientist, or the plethora of professions that contribute greatly to society.