Naturalization of oppressions and of marginalizations are common in class society. Women, homosexuals, Blacks, Latinos, Asians, Muslims, etc. have all been seen by the prejudiced to have a deficit in comparison to the mythical norm of what a human being is supposed to be.
There is a parallel between the disabled and non-English-speaking immigrants, to take just one example. You complained of immigrants who speak Farsi, Russian, Spanish, etc. rather than English. The inability or unwillingness of some immigrants to speak English is seen as _their_ deficit, no matter how many other languages immigrants speak and how well they speak them, rather than as the linguistic deficit of the monolingual American-born. In the same way, many treat the disabled as if the disabled had a deficit, rather than seeing a deficit in themselves or their society that disables people.
-- Yoshie <http://montages.blogspot.com/> <http://mrzine.org> <http://monthlyreview.org/>